Australia Post employee Stephen Hodge was shot dead by an officer at Lake Macquarie after coming at him with a kitchen knife in September 2015.

Deputy state coroner Teresa O'Sullivan handed down her inquest findings on Friday and suggested NSW Police provide more training so officers could better deal with mentally ill people in emergency situations.

"Police have an extremely difficult job to do and often very little time to plan and find out all the information they need, particularly about someone's mental health," she told Glebe Coroner's Court.

Two plain-clothes officers had been called to the scene after reports the knife-wielding 51-year-old had threatened his manager at the Warners Bay post office.

Mr Hodge had chased postmaster Brendan Hogan outside the store with the large knife after an argument before slashing his own wrist on the afternoon of September 9.

Senior Constables Jamie Taylor and Darren Hamilton pleaded with Mr Hodge to drop the weapon in the car park as he came at them.

Within 40 seconds they opened fire, with Sen Const Taylor fatally hitting him in the chest and abdomen.

Sen Const Hamilton fired three shots with one bullet missing Mr Hodge.

"There was no other available tactical option," the coroner found.

The officers did not ask Mr Hodge his name, what he wanted or where the postmaster was, the inquest previously heard.

In the moments after Mr Hodge's death, the officers were confronted by his angry mother who said: "Why did youse do this? He wouldn't hurt anyone. Why?"

The coroner found there was a "toxic" amount of antidepressants in the alcoholic's system.

She couldn't say whether Mr Hodge had tried to provoke the officers into ending his life by shooting him.

"Mr Hodge's death was tragic," Ms O'Sullivan said.

"It has deeply affected his family, his work colleagues and the police involved."

Janet Hodge, who was 79 when her son was killed, refused to attend the inquest or provide a statement.

But she later told a police officer that her son called her moments before he attacked his boss and told her: "You're going to see me on the news tonight."

Detective Chief Inspector David Laidlaw, who investigated the incident, said NSW Police would consider the recommendation for additional training.

The police union said the coroner "missed an opportunity" to examine the failure of the mental health system by focusing on the officers' response.

"It's critically important that - not only police - but all agencies are reviewed and scrutinised," Police Association NSW president Scott Weber told reporters.

"There was a beginning, middle and end to this incident. There have been systemic problems in regards to mental health and looking after the most vulnerable people in our community."

Australian Associated Press