THREE paramedics have contradicted police evidence about how a mentally ill man who was harming himself was fatally shot by an officer in a Sydney home.

Paramedic Cheri Lutz was standing over Adam Salter, 36, when he got up from the kitchen floor, fought off his father and reached for a knife in the sink, a Police Integrity Commission (PIC) inquiry heard on Tuesday.

Mr Salter was being treated for a self-inflicted stab wound to his chest at his family's Lakemba home in November 2009, when he began stabbing himself in the neck.

Ms Lutz and her two colleagues then saw Sergeant Sherree Bissett enter the kitchen, yell out "Taser" and shoot Mr Salter in the back with her handgun.

"There was a loud bang," Ms Lutz told a Police Integrity Commission (PIC) investigation on Tuesday.

"He immediately fell to the ground."

She told the PIC that Probationary Constable Aaron Abela, who was the only officer in the kitchen before the victim got up, did nothing to restrain him.

Mr Salter was not warned to stop and was not restrained before he was shot, Ms Lutz said.

He did not wield the knife at police or threaten anyone but himself, she said.

Her colleague Karl Johnstone was treating Mr Salter on the floor when the commotion erupted.

"Did you see a policeman grab Adam ... ?" counsel assisting the PIC, Geoffrey Watson, asked.

"I didn't see that, no," Mr Johnstone replied.

"Did you see that policeman move at all?"

"No," he said.

Constable Abela has given evidence that he tried to restrain Mr Salter, while Sgt Bissett has testified that Const Abela tried to restrain Mr Salter, and Mr Salter was about to stab Const Abela.

"Did you see Adam Salter lunging at police with the knife?" Mr Watson asked.

"No," Mr Johnstone said.

"Did you see Sgt Bissett challenge Adam to put down the knife?"

"No," he replied.

Mr Johnstone also said he did not see Mr Salter brandish or swing the knife at police.

Paramedic Megan Coolahan, who was also present in the kitchen, gave a similar account to the PIC on Monday.

Mr Watson told the PIC that his questions stemmed from allegations police made in internal reports and statements to the media after the incident.

The commission is investigating the incident, the statements given by police involved, the ensuing investigation and two internal reviews of the investigation.

It will also probe why police did not refer the matter to their Professional Standards Command after a coronial inquest delivered a scathing finding about the incident, the investigation and the subsequent reviews.

The hearings continue.

Originally published as Police shooting victim 'not warned'