Newcastle District Court judge Tim Gartelmann on Friday accepted psychiatric evidence that Oliver Scales-Copeland was suffering from disorganised thinking and paranoid delusions when he attacked the policemen in 2019.

He said Scales-Copeland "on the balance of probabilities" had been aware of what he was doing when stabbing the officers, but not criminally responsible because he did not know it was wrong.

Scales-Copeland did not trust the police, feared they were trying to kill him and believed he was acting in self-defence.

The judge ordered the 26-year-old continue to be detained in Long Bay jail's psychiatric hospital as a forensic patient until his case was assessed by the Mental Health Review Tribunal.

He said Scales-Copeland could not be released at this stage as he remained a danger to others because of his limited insight into his mental illness despite treatment.

It would be up to the Tribunal to decide when he should be freed.

Two Sydney psychiatrists, Dr Olav Nielssen and Dr Richard Furst, had diagnosed Scales-Copeland with chronic schizophrenia and substance abuse disorder.

They said his cocaine use had made his schizophrenia worse before the attack but he had been mentally ill for a number of years.

He claimed he was awake all night after taking cocaine before driving from Sydney to Lake Macquarie on Sunday, October 6, and attacking the two senior constables about 1pm outside a Toronto service station.

Judge Gartelmann found Scales-Copeland, from Bronte in Sydney's east, not guilty due to mental illness to two counts of wounding with intent to prevent arrest.

Scales-Copeland, the son of Greens councillor George Copeland on Sydney's Waverley Council, had been wearing only red underpants when he began threatening motorists with a knife before the two police officers approached him at the Caltex service station.

When ordered to drop the knife, he called out, "come on dogs, I'll take you on".

The officers used capsicum spray and a baton to try to disarm Scales-Copeland and were wrestling with him when he stabbed one officer five times in the left thigh and the other officer once in the right hand, cutting one finger to the bone.

Both officers opened fire but missed before he was arrested with the help of bystanders.

When later questioned by detectives, Scales-Copeland claimed to have no memory of stabbing the officers.

He told police he had to get out of Sydney because he realised the city was under a hole in the ozone layer and it was unsafe.

Australian Associated Press