An inquiry into the police shooting of a mentally ill Sydney man is recommending charges against four officers.

Adam Salter was shot dead by police in his Lakemba home in 2009.

Police said the mentally ill man had come at them with a knife, but a coroner found the 36-year-old been stabbing himself.

The Police Integrity Commission (PIC) has been investigating allegations of a police cover-up.

In a report tabled in the New South Wales Parliament today, it has found the police internal investigation was biased and a subsequent review was lax.

The PIC is calling on New South Wales Police to take action against seven officers for misconduct.

It says four of them should be charged for knowingly giving false evidence.

A number of senior police are among those who have been criticised, including high-profile homicide detective Russell Oxford.

The police corruption watchdog has also called on New South Police to lift the veil of secrecy on its internal investigations.

It recommends New South Wales Police publish all their critical incident investigation reports online.

The report also lends its support to calls for the establishment of an independent body to investigate critical incidents, but says it is up to the State Government to decide whether the high cost involved would be warranted.

The State Government is considering handing over internal police investigations to an independent body.

Police Minister Mike Gallacher says the Government is looking at the PIC's recommendations.

"I can assure the house that this matter, the critical incidents issue in relation to the NSW police will form part of the review of the police act that the member would be aware of," he said.