Three people have been burnt to death and another is fighting for his life with critical facial and head injuries after a high-performance car crashed off a bridge and caught fire in Sydney’s Darling Harbour.

Police said a Nissan GTR carrying four people was driving up the Pier Street Bridge in central Sydney when it crashed into a rail, then into the side of a building before flipping upside down and catching fire about 3am on Saturday.

Police and emergency services doused the car’s burning occupants but only managed to pull a 39-year-old Leichhardt man free. He is fighting for his life in St Vincent’s Hospital with extensive facial and head injuries and several broken ribs.

Two men and a woman who died are yet to be identified.

NSW Police Superintendent Paul Pisanos said the trio “effectively have been burnt alive”.

“The sad part about it is … somewhere across Sydney there are people waking up (whose) sons and daughter haven’t arrived home from a night out in the city,” he told reporters on Saturday.

Superintendent Paul Pisanos confirmed “speed – and considerable speed at that – along with a loss of control are two contributing factors [in the crash]”.

He added that three young male officers and a female colleague who tried to save the occupants who had caught alight inside the car had been extremely traumatised.

“Imagine today they’re pondering over their own actions and whether they could do more, which is quite unfortunate,” he said.

“A 39-year-old man, who was among the passengers, was pulled out of the vehicle by police, before it became engulfed in flames,” an earlier police statement said.

“He was treated by NSW Ambulance paramedics before being taking to St Vincent’s Hospital with lacerations and burns to his body and remains in a serious but stable condition.”

Peter Sergent, a guest at the nearby Novotel Hotel, told the ABC he thought a bomb had gone off when he heard an explosion from the car.

“We looked out our window and below us was a fire,” he said.

“We were told to evacuate the hotel…. the stairwells in the hotel were all full of smoke.”

Mr Sergent said he saw a man being dragged from the car wreck and another witness said he heard the car’s tyres screech just before it crashed.

“It just woke us up and we heard the car screaming and the engine revving out and then it just went bang and hit the building and stopped dead — no brakes, no anything — and it smoked and then in a few minutes it burst into flames,” he said.

It’s believed the vehicle travelled down Goulburn Street at speed before the driver lost control and hit an overpass barrier on Pier St.

The car then appears to have rotated mid-air, before it landed on its roof and ignited.

“These, unfortunately, are extreme cases that illustrate that excessive speeds and the manner of driving in built-up areas and any road in NSW can lead to catastrophic consequences,” Superintendent Pisanos said.

—with ABC/AAP