Moment man douses himself in petrol and sets himself alight

Police have used fire extinguishers on a protestor who set himself on fire in front of people at lunchtime in Sydney.

The horrific scene unfolded outside the Department of Immigration offices near Central Station.

Confronting images have been released by NSW Police to show how they responded to the incident.

A man set himself on fire in Sydney CBD on Friday afternoon. Photo: NSW Police

Minutes before, seven police officers had tried negotiating with the protestor, who incredibly only suffered superficial burns.

The flames burned for seconds before police officers put them out.

Police rush to put the man out. Photo: NSW Police

"We were watching it from the tenth floor, he was just sitting against that railing and all of a sudden, just a ball of fire," one witness said.

Investigators have not yet said what the man, aged in his 30s, was protesting about.

The man set himself alight outside the Immigration building on Lee Street in Sydney. Photo: Google Maps

A witness said the man was on fire from his thighs up to mid-stomach.

He is in hospital being checked over fears he may have breathed in flames, damaging his lungs.

Police released the video to prove they had responded quickly.

The man was taken out on a stretcher. Photo: Twitter / 2GB.

"This incident demonstrates the brave police officers on a daily basis across our state responding to very difficult self-harm jobs from mental health patients," Detective Superintendent David Donohue said.

"On each occasion our goal is to resolve these matters peacefully."

If you are concerned about the mental health of yourself or a loved one, seek support and information by calling Lifeline 13 11 14, the Suicide Call Back Service 1300 659 467, or Beyond Blue 1300 22 46 36.