Two workers have managed to escape uninjured from a popular waterfront restaurant, Milano’s On The Lake, just before it partially collapsed into a lake south of Newscastle.

The pier underneath Milano’s On the Lake at Pelican on Lake Macquarie collapsed just before 10 a.m. on Monday while two restaurant workers were still inside, The Guardian reported.

Minutes after the collapse, Milano’s On The Lake posted an announcement on Facebook. “Everyone is OK, just here with emergency services now.” Multiple emergency crews responded immediately after the building partially collapsed into the water. Emergency crews turned off gas and electricity to the two-storey building to prevent any further risks, Yahoo News Australia reported.

Two workers were inside when 'Milano's On The Lake' partially collapsed. Photo: Fire and Rescue NSW

Two workers were inside when ‘Milano’s On The Lake’ partially collapsed.
Photo: Fire and Rescue NSW

“We have isolated the power and gas and are in the process of preventing oil going into the lake,” NSW Fire and Rescue Superintendent Ian Krimmer said.

Booms have been set up to prevent contamination in the water around the popular wedding and function centre.

According to The Guardian, an engineer will assess the building, which was already damaged in 2013 when a fire broke out in the adjacent boat-for-hire business.

Jim Sommers, who works on the marina, told ABC News he left his office, Marine Solutions, just 10 minutes prior to the partial collapse, and “didn’t hear any creaks or bangs or anything” in the preceding hours. “I think it’s just something, a straw that’s broken the camel’s back and away she’s gone,” Sommers said.

Superintendent Krimmer said that divers will also be needed to conduct the assessment of the collapsed structure.

“It collapsed into the water and obviously something dramatic has happened underneath. Now that will be the job of divers and engineers. It could be some time before a full picture comes to view of exactly what has happened,” Krimmer told ABC News.