Victoria wakes to first morning of new lockdown

Victoria has woken to its first morning of a seven-day "circuit breaker" lockdown, after new restrictions came into force at midnight.

The closure confines more than six million people to their homes, with limited exceptions, until 11.59pm on June 3, in an attempt to control an outbreak that had spread to 26 people by Thursday.

As the number of exposure sites passed 150 and contact tracers linked 10,000 primary and close contacts to the cluster, Acting Premier James Merlino said yesterday "very strong advice" from public officials had compelled a statewide lockdown.

EXPLAINED: What you can and can't do for the next week in Victoria

"No one wants to be in this position, but I think the community also understands that we've got to follow public health advice," he said.

"We've seen overseas what happens if this thing gets away. We must follow public health advice.

"My view is that as tough as this is for everyone, I think people appreciate that we just got to do this."

All of the cases in the outbreak were linked to either households, the Stratton Finance workplace or through casual links to the City of Whittlesea, Victoria's Chief Health Officer Professor Brett Sutton confirmed.

"That's very reassuring. That's great work of contact tracing."

More than 40,000 tests were processed on Wednesday and the government announced the number of testing sites had been increased to almost 200, almost a quarter of them running to extended hours.

But that didn't stop queues forming from the early hours of Thursday. The Melbourne Showgrounds site reached capacity in just 26 minutes and drivers turning up after 9am were told to expect a four-and-a-half-hour wait at Albert Park.

"Some of the queues looked like they were pretty long so I decided to bite the bullet, get up early and get it done," one testee told 9News.

Victorians now only have five reasons to leave home: shopping for food and supplies, authorised work, care and caregiving, exercising with one other person for up to two hours and getting vaccinated or tested.

Victorians in their 40s are eligible for the Pfizer vaccine.

"I really encourage everyone, if you're eligible, get vaccinated," Mr Merlino said.

Lines also formed on Thursday at the airport and some hit the road as they tried to bring forward holiday plans to escape the restrictions.

"We thought we'd get out of Melbourne as quick as possible," one lady told 9News on the way to Deniliquin in New South Wales.

There were delays of between two and three hours at a South Australian border checkpoint heading west on the Dukes Highway.

Most were South Australians heading home but the queues also included some regional Victorians looking to escape the lockdown and travellers caught out by the snap measures.

At the airport, holidaymakers tried their luck at escaping despite Qantas and Virgin cancelling more than 25 flights in and out of Melbourne.

"I just want to get out, please let us out … I haven't been to any exposure sites, I haven't been near anyone, I just want to go on holiday – I've cancelled three times," one woman said.