A Hastings resident said the sound of a giant warehouse roof caving in sounded like a 'train crash'.
Emergency services and contractors rushed to Caroline Rd in Hastings yesterday and cordoned off surrounding streets when the two-storey cool store buckled and its walls bowed about midday.
Neighbours and residents grouped behind police cordons as power was shut off and engineers were sent in to evaluate the building structural integrity.
One resident living on Caroline Rd said the loud noise of the roof giving way made him think there'd been a 'train crash'.
Fire and Emergency area commander Ken Cooper said they would be present throughout the night in case the building collapsed.
"We're concerned for public safety and the collapse of this building, cordons will remain in place. We've got our search and rescue technicians responding from our central base in Palmerston North.
We've got monitoring equipment that we'll set up overnight to tell us whether the building is moving and then we're going to assess our options first thing in the morning."
Cooper said it was more than likely that the building would be demolished and emergency services would be standing by.
KiwiRail services were halted from operations due to safety risks, but Cooper said they were in constant contact with all buisnesses affected.
The premises is leased by Polarcold and CEO Steve Foote said that no staff members were in the building when the roof collapsed, and that the building would remain cordoned off to protect members of the public.
"None of our staff or contractors were in there or on the site, so there's no implications for health and safety and that was our number one concern.
This is an issue for the building owner and he'll be talking to engineers and they're working through the problem with the building."
Foote said the warehouse was used to store frozen goods.
A neighbour who lived around the corner said contractors had been working on re-strengthening the building for over a year, but the work had never been completed.
"I've seen cranes coming and going a few times-but the work has just been going on for ages."
Unison relationship manager Danny Gough said they made the call to disconnect power to the surrounding area just before midday.
"We were notified by the police shortly after the incident happened and they were concerned for public safety in terms of the stability of the building and the surrounding properties.
We've de-energised the power purely in the interest of public safety, in case the building did fall across existing powerlines or collapsing among itself creating a fire within its own electrical system," he said.
About six customers were affected and the power was restored to the area just after 4pm.
Anthony Bourke from Seeds & Cereals which neighboured the slumped building said he had to shut up shop for the day due to the power cut.
A police officer at the scene said the building was "extremely unstable" and could give way at anytime.
In a typical kiwi fashion, other keen watchers pulled out their deck chairs and enjoyed a cool beverage in the sunshine while watching the commotion; others simply continued playing touch rugby in the front yard, ignoring the assembling firefighters on the footpath.
A fire communications officer said two appliances were initially called to the scene of the building but only one remaining appliance was at the scene at about 4pm yesterday.