A former client allegedly targeted a law firm on the New South Wales Central Coast with homemade explosives, leaving staff traumatised.

Gary Steven Middleton, 66, was arrested and charged yesterday for allegedly setting fire to two offices in Gosford using LPG cylinders on Thursday.

Several gas cylinders had been allegedly set alight inside Conditsis and Associates, causing doors to blast off their hinges and thick smoke and flames to engulf the building.

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It left the 20 staff inside at the time scrambling for safety.

Police alleged Middleton set off the homemade explosives inside the law firm, which had previously represented him, after they cut ties with him as a client.

Conditsis and Associates said staff had been left traumatised.

"The incident was traumatic for all our staff and we are so grateful that no one was seriously physically injured or worse – it was a miracle," Conditsis and Associates' director Manny Conditsis said in a statement.

The Legal Aid office on Donnison Street was also allegedly set alight just before 2.30pm on Thursday.

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Gosford Courthouse and Director of Public Prosecutions offices were temporarily closed as a precaution until police tracked down Middleton to his Wallarah home and charged him.

Middleton had been on strict bail since April and is facing a raft of serious charges.

He was due to be sentenced yesterday, a day after the alleged arson attack, for those charges.

Now, Middleton is facing two counts of destroying or damaging property with intent to endanger life, which carries a maximum penalty of 25 years imprisonment.

The 66-year-old did not apply for bail when he faced Parramatta Local Court today.

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Woolworths has reached an agreement with the United Workers Union after staff walked off the job more than two weeks ago.

More than 1500 warehouse workers went on strike to improve their pay and conditions, which resulted in reduced stock on supermarket shelves.

A spokesperson for the supermarket giant said the distribution centre in Dandenong South in Victoria could re-open tonight, after the company's new enterprise agreement offers were endorsed by the United Workers Union (UWU) this afternoon.

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"The Melbourne Liquor Distribution Centre, Wodonga Regional Distribution Centre and Erskine Park Distribution Centre are also expected to re-open soon," the supermarket said in a statement.

"All four sites will be stood back up to full capacity as soon as possible.

"Votes on the new deals will be put to teams at these sites as soon as possible."

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Woolworths said the industrial action had impacted the supply of products in its stores across Victoria, ACT and parts of NSW.

"With just over two weeks to go until Christmas, we're now focused on getting products out of the distribution centres and restocking the empty shelves customers have experienced in the past fortnight," CEO Amanda Bardwell said.

"Turning back 'on' such a large part of our supply chain will mean it will take some time for our stores to look their best and we'll be ramping up as much as we can to get products to the stores where they're needed most."

The UWU said the strike was "primarily about addressing workers' concerns with Woolworths Framework", which is a performance management program that monitors pick rates at warehouses.

A spokesperson said a new clause would be added to workplace agreements that "ensures workers will not be disciplined for the speed that they can work at".

The spokesperson said workers had also secured "above-inflation increases" across all sites "to help families in a cost-of-living crisis".

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"Today, warehouse workers at Woolworths have saved Christmas," the UWU said. 

"But more importantly, they have challenged one of the most significant threats to worker safety and well-being as we enter a new AI-surveillance era of work, and they have won.

"This has been a very hard struggle to get to this point, with workers forgoing pay on strike for 17 days."

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