At least 110 people have died in devastating floods across parts of western Germany and Belgium, officials said Friday, as search and rescue operations continued for hundreds more still unaccounted for or in danger.

Authorities in the German state of Rhineland-Palatinate said 60 people had died there, including 12 residents of an assisted living facility for people with disabilities in the town of Sinzig who were surprised by a sudden rush of water from the nearby river Ahr. In neighbouring North Rhine-Westphalia state officials put the death toll at 43, but warned that the figure could increase.

German President Frank-Walter Steinmeier said he was "stunned" by the devastation caused by the flooding and pledged support to the families of those killed and to cities and towns facing significant damage.

READ MORE: More than 60 dead, dozens missing in European floods

"In the hour of need, our country stands together," Steinmeier said in a statement Friday afternoon. "It's important that we show solidarity for those from whom the flood has taken everything."

Rescuers rushed Friday to help people trapped in their homes in the town of Erftstadt, southwest of Cologne. Regional authorities said several people had died after their houses collapsed when the ground beneath them sank suddenly. Aerial photos showed what appeared to be a massive sinkhole.

"We managed to get 50 people out of their houses last night," county administrator Frank Rock said. "We know of 15 people who still need to be rescued."

Speaking to German broadcaster n-tv, Rock said that authorities had no precise number yet for how many had died.

"One has to assume that under the circumstances some people didn't manage to escape," he said.

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Authorities said late Thursday that about 1300 people in Germany were listed as missing, but they cautioned that the high number could be due to duplicated reports and difficulties reaching people because of disrupted roads and phone service.

In a provisional tally, the death toll in Belgium rose to 12 and five people were missing, local authorities and media reported early Friday. Most of the drowning victims were found around Liege, where the rain hit hardest.

Flash floods this week followed days of heavy rainfall which turned streams and streets into raging torrents that swept away cars and caused houses to collapse across the region.

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Thousands of people remained homeless in Germany after their houses were destroyed or deemed at-risk by authorities, including several villages around the Steinbach reservoir that experts say could collapse under the weight of the floods.

The governor of Germany's North Rhine-Westphalia state, Armin Laschet, called an emergency Cabinet meeting Friday. The 60-year-old's handling of the flood disaster is widely seen as a test for his ambitions to succeed German Chancellor Angela Merkel after the country's national election on September 26.

Malu Dreyer, the governor of Rhineland-Palatinate state, said the disaster showed the need to speed up efforts to curb global warming. She accused Laschet and Merkel's centre-right Union bloc of hindering efforts to achieve greater greenhouse gas reductions in Germany, Europe's biggest economy and a major emitter of planet-warming gases.

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"Climate chance isn't abstract anymore. We are experiencing it up close and painfully," she told the Funke media group.

Steinmeier called for greater efforts to combat global warming.

"Only if we decisively take up the fight against climate change will we be able to limit the extreme weather conditions we are now experiencing," he said.

Experts say such disasters could become more common due to climate change.

"Some parts of Western Europe…received up to two months of rainfall in the space of two days. What made it worse is that the soils were already saturated by previous rainfall," World Meteorological Organisation spokesperson Clare Nullis said.

While she said it was too soon to blame the floods and preceding heat wave on rising global temperatures, Nullis added: "Climate change is already increasing the frequency of extreme events. And many single events have been shown to be made worse by global warming."

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Defence Ministry spokesman Arne Collatz said the German military had deployed over 850 troops as of Friday morning, but the number is "rising significantly because the need is growing." He said the ministry had triggered a "military disaster alarm," a technical move that essentially decentralises decisions on using equipment to commanders on the ground.

Italy sent a team of civil protection officials and firefighters, as well as rescue dinghies, to Belgium to help in the search for missing people from the devastating floods.

The firefighters tweeted a photo of one team working in Tillf, south of Liege, to help evacuate residents of a home who were trapped by the rising waters.

In the southern Dutch province of Limburg, which also has been hit hard by flooding, troops piled sandbags to strengthen a 1.1km stretch of dike along the Maas river and police helped evacuate some low-lying neighbourhoods.

READ MORE: NSW towns swallowed by 'inland sea' after flooding

Caretaker Prime Minister Mark Rutte said Thursday night that the government was officially declaring flood-hit regions a disaster area, meaning businesses and residents are eligible for compensation for damage.

Dutch King Willem-Alexander visited the region Thursday night and called the scenes "heartbreaking".

Meanwhile, sustained rainfall in Switzerland has caused several rivers and lakes to break their banks. Public broadcaster SRF reported that a flash flood swept away cars, flooded basements and destroyed small bridges in the northern villages of Schleitheim und Beggingen late Thursday.

Erik Schulz, the mayor of the hard-hit German city of Hagen, about 50km northeast of Cologne, said there had been a wave of solidarity from other regions and ordinary citizens to help those affected by the devastating floods.

"We have many, many citizens saying 'I can offer a place to stay, where can I go to help, where can I registered, where can I bring my shovel and bucket?'," he told n-tv. "The city is standing together and you can feel that."

Mel Rudkiewicz is back on Australian soil but still separated from her dying mum.

Ms Rudkiewicz is on day four of hotel quarantine in Sydney after returning from Los Angeles while her mum is in Adelaide battling stage 4 cancer and her condition is deteriorating every day.

"My biggest fear really is that I'll be stuck in quarantine and I'll get a text from my dad that she's gone," Ms Rudkiewicz told 9News.

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"I'm perfectly healthy, I'm fully vaccinated and I'm just so terrified that I'm never going to see her again."

It's not that Ms Rudkiewicz left it too late to travel home to be by her mother's side.

Her mum's diagnosis was a shock — by the time doctors discovered the cancer in her liver and pancreas, they gave her just weeks to live.

"It's been two years since I've seen her and this was nothing that was ever anticipated," Ms Rudkiewicz said.

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In her battle to get exemptions to travel to South Australia, Ms Rudkiewicz's now received a heartbreaking ruling from NSW Health.

The only way she can come home early to Adelaide is to charter a private jet. And the cheapest option for that costs $7000 one way.

Ms Rudkiewicz would also still need special permission from SA Health.

When asked if it was considering her case, the department did not comment but referred 9News to the general rules for all travellers.

"I feel completely gutted and exhausted," Ms Rudkiewicz said. "I feel like I'm pursuing every avenue possible."

If no help from health authorities is forthcoming, Ms Rudkiewicz has an agonising 10 days left to wait.

"I'm just so scared I'm going to have that opportunity robbed of me."

Sydney is on the verge of even tougher new COVID-19 lockdown restrictions, with crisis meetings being held as New South Wales struggles to contain an outbreak of the Delta strain.

9News understands the state government is considering measures such as police checkpoints, cameras that read number plates, and shutting down all retail across Greater Sydney to combat the high number of people who have been moving around in the community whilst infectious after the state recorded 97 new cases today.

"It has been conceded by the government that the current lockdown is not doing the job it needs to, so they will go harder," 9News political reporter Chris O'Keefe said.

"A few of the options are shutting retail across Greater Sydney and forbidding certain types of work, otherwise a more localised lockdown of the Fairfield area going as far as having police checkpoints and cameras which can read number plates, fining people if they leave the area."

It comes as the Australian Medical Association recommended NSW enforce a "Victorian style lockdown".

Dr Omar Khorshid said a harder lockdown was needed to stop people circulating in the community who may be infectious with the COVID-19 Delta strain if it has a chance of coming out of lockdown.

Of today's cases, fewer than half were isolated throughout their entire infectious period, sparking concern the stay-at-home order isn't doing enough to reduce infection numbers.

Premier Gladys Berejiklian hinted at yet another rise in daily infections, warning NSW residents she would not hesitate to do whatever it takes to stop the spread.

Twenty-nine cases were out in the community for two or more days while infectious, 17 were partially isolated and the isolation status of five cases remains under investigation.

There have now been more than 1000 community COVID-19 infections since the Delta variant began spreading through Sydney, one month ago today.

Ms Berejiklian described today's figures as "concerning", noting that the percentage of people infectious while in the community has continued to rise.

"I can't stress to the community enough my absolute concern that we need to work harder at reducing mobility and reduce our interactions with others if we will bring the situation under control," Ms Berejiklian told today's press conference.

The results follow a huge testing push in Sydney's south-west, the current epicentre of the outbreak.

There were 77,587 tests reported to 8pm yesterday – up by almost 20,000 from the previous day.

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https://twitter.com/NSWHealth/status/1415838782989893635?ref_src=twsrc%5Etfw

"I am assuming because we had, in the last 24 hours, at least 29 of those 97 cases were infectious in the community, the numbers tomorrow will be greater than what we saw today," she said.

"We have never ever been afraid of taking the difficult decisions to make our community safe.

"It will be based on the health advice."

However, Ms Berejiklian expressed doubt about the necessity of requiring masks outdoors.

"To date, we don't know of anybody who has transmitted or received the virus while they are exercising," she said.

But Chief Health Officer Dr Kerry Chant said people need to have a mask with them whenever they leave the house and wear them while waiting for a takeaway coffee or in similar circumstances.

Fairfield in Sydney's south-west remains the hardest-hit region, with roughly 75 per cent of today's cases coming from the local government area.

However, it is not the only area of concern.

Bayside, Campbelltown, Camden, Lakemba, Fairfield, Liverpool, Cumberland, Mt Druitt, Rooty Hill, the Sutherland Shire and the Georges River area have all be named areas where the Delta variant is circulating.

https://twitter.com/NSWHealth/status/1415838799829954560?ref_src=twsrc%5Etfw

Dr Chant urged Sydneysiders not to assume they were safe leaving home because they weren't in a hotspot area.

"We need to remember that the cases we are seeing today reflect transmission evidence for five days ago," she said.

"You can't go on the basis of where I have told you as a hotspot today."

Unlinked cases a cause for concern

Two more people have been admitted to hospital with the virus since yesterday, making 75 in total.

Of these patients, 18 are in ICU and five require ventilation. Out of those 18, one has had one dose of AstraZeneca vaccine.

The others are unvaccinated.

Today's spike follows a brief dip in daily numbers yesterday, with 65 new cases recorded.

Around half of coronavirus cases today were household contacts of previously confirmed cases and a further 14 were close contacts, but 34 cases – or just over a third – remain under investigation.

"We have a number of cases under investigation and seeing the emergence of unlinked cases which is a matter for concern," Dr Chant said.

"The fact 29 cases were infectious for two or more days in the community is incredibly concerning."

Ms Berejiklian is calling on anyone who has a coronavirus infection among their extended family, workplace or social circle, to come forward to be tested.

She warned Sydneysiders not to try and sneak out to regional areas.

"The regions have done exceptionally well in not having the virus," she said.

"We've been able to keep them out of lockdown."

It comes as Australia's two biggest cities are simultaneously in lockdown for the first time this year, with Melbourne trying to contain an outbreak that originated in NSW.

COVID-19 spreading at workplaces

NSW health authorities are warning that workplaces are now the key mode of COVID-19 spread in Sydney, with anyone who can work from home urged to do so.

Workers unable to do so are being reminded to wear a mask at all times, including indoors and outdoors on construction sites and to stay up-to-date with hotspot locations on the NSW Health website.

Close interaction between staff members is to be minimised, with meetings and gatherings avoided and group sizes minimised.

https://twitter.com/NSWHealth/status/1415838810336727040?ref_src=twsrc%5Etfw

Dr Chant said that the spread of the virus within retail settings hasn't been a feature of this outbreak in recent weeks.

The only instances of this occurring since lockdown began was inside the Commonwealth Bank store in Roselands, where a staff member worked on multiple days while infectious.