Extreme heat from a basement fire at Sydney’s Barangaroo construction site is preventing firefighters from locating the cause of the blaze, which is threatening to collapse a multi-storey crane.

Authorities and developers Lend Lease say all workers from the site have been evacuated and there are no reports of injuries, while buildings around the site are also being emptied.

More than 100 firefighters and 20 trucks are pumping water form surrounding streets to extinguish the blaze and targeting the bottom of the crane, which has been burning since 2pm.

A firefighter dousing the base of the crane in water at Barangaroo. Photo: Getty

The fire has forced a thick plume of smoke hundreds of metres in the air with about 500 site workers and 2,000 office workers from nearby buildings evacuated.

“That crane has been exposed to an amount of heat and our engineers inform us that if it continues to be exposed to heat there could be a risk of the crane collapsing,” Fire and Rescue spokesman Ian Krimmer said at the scene.

“For that reason we have evacuated the surrounding areas.”

The crane is estimated to be about 25 storeys high at its current extension.

The fire is burning across two levels of the site, however the heat is so strong thermal imaging cameras have “blown out” and are unable to pinpoint the seat of the blaze.

Hazmat crews are monitoring the smoke, while lasers aimed at the top of the crane will tell rescuers if it moves or not.

“Crane collapses can be quite dramatic if they occur,” Mr Krimmer said.

“They tend to twist and then topple over. That twisting means we can’t predict where it will fall, if it was to fall.”

Fire trucks have been fighting the blaze since it erupted at the harbourside site around 2pm, forcing the evacuation of workers and nearby buildings.

Emergency crews have sealed off parts of Hickson Road and the western distributer has also been shut because of concerns about the crane.

Two hotels near the site have also been evacuated.

Seems someone doesn’t like the #Barangaroo development. #fire pic.twitter.com/E89XwUCF3X

— Paul Upham (@pauljupham) March 12, 2014

Gotten worse, the smoke is a lot darker now #fire #barangaroo pic.twitter.com/FriMULw69W

— Ty Yilmaz (@yilmaz16) March 12, 2014

Superintendent Krimmer said water had been diverted to the scene to battle the fire and water from the harbour may also be used.

“We’re pumping water from surrounding streets into this area,” he said. “Our strategy is to contain this fire to ensure stability of the crane.”

He said firefighters were facing a tough job in putting out the basement fire were still trying to get to the seat of it.

“It’s extremely hot. Any firefighter knows that basement fires are our worst nightmare, there is nil visibility … it’s all by touch and feel.”

Supt Krimmer said a thermal camera will be used to try and get a view inside the basement. He said all workers had been evacuated and there were no reports of injuries so far.

The fire is belching smoke hundreds of metres into the sky.

Company checking staff

A spokesman for Lend Lease, the site developer, said the company was conducting a roll call of staff.

Spokesman Dan Labbad said the company was helping authorities to evacuate buildings affected by the smoke billowing from the southeast of the construction site.

“At this stage we don’t have all the facts,” he said.

“There are a number of buildings that are potentially at risk and we’re evacuating those buildings now.”

The area is being redeveloped as a residential and retail hub, with plans for a high-rollers’ casino owned by billionaire James Packer.

The Sydney Morning Herald is reporting the Lend Lease site on fire was to be the new Tower 3, or T3, and that accounting firm KPMG was to move into the building on completion.

Traffic info

Motorists have been warned by the NSW Transport Management Centre to avoid driving through central Sydney and the busy Western Distributor Freeway has been closed.

Images posted to social media show flames and smoke pouring out of the basement of an under-construction building on Hickson Road.

Crane at risk

There have been various reports that the crane is at risk of collapsing as a result of the fire but NSW Fire and Rescue said there is no imminent danger and they are taking the necessary precautions to protect the area.

Fire and Rescue NSW Superintendent Ian Krimmer said all workers had been evacuated from the site and there were no injuries reported.

Redevelopment

The area is being redeveloped as a residential and retail hub, with plans for a high-rollers’ casino owned by Packer.

Lend Lease, who is building the development, saw it’s share price drop 2.2 per cent, as the market reacted to news of the fire.

Twitter was also flooded with photos and reports of intense smoke coming from the area.

Market reacts to fire at #barangaroo https://t.co/qwAZsPkThf pic.twitter.com/Ztu0wr3fr6

— Emily (@emilyguterres) March 12, 2014

Seems someone doesn’t like the #Barangaroo development. #fire pic.twitter.com/E89XwUCF3X

— Paul Upham (@pauljupham) March 12, 2014

BREAKING LIVE : @LendLeaseGroup Global COO San Lebadd responds to #Barangaroo fire. Shares -2.28%. #ausbiz (@carsonscottLIVE)

— Sky News Business (@BusinessChannel) March 12, 2014

#Barangaroo is on fire. Apparently the smoke seems to be coming from below the ground of the construction site. pic.twitter.com/Rw8ylOmFa7

— Maddi Easterbrook (@mmmeasterbrook) March 12, 2014

Fire at #Barangaroo in #Sydney pic.twitter.com/aRzmgMqUp6