Michael Capel, 43, was shot five times in a Belmont caravan park after police took nearly six hours to respond to his family's pleas for urgent help after the schizophrenia sufferer assaulted his mother, Elma Heath.

Deputy State Coroner Paul MacMahon found yesterday that Mr Capel's death could have been prevented if it had been realised that he had failed to take medication for nearly two months.

Mr MacMahon recommended special mandatory training for front-line police dealing with mentally-ill patients.

He also recommended that mental health teams ensure GPs have follow-up procedures when patients on anti-psychotic medication fail to turn up for their doses.

Mr Capel, who had never had a violent psychotic episode since being diagnosed with schizophrenia when he was 23, had missed two monthly appointments with his doctor when he assaulted Mrs Heath on October 10, 2008.

Six hours later Mr Capel was dead, shot five times by Senior Constable Jason Battle after he and his partner Senior Constable Sally Hogg arrived to be confronted by Mr Capel threatening them with a knife.

Bringing down his findings, Mr MacMahon found both officers had "acted reasonably in the circumstances and that no criticism of their actions is warranted".

He also found that the 5?-hour delay before police arrived had not aggravated the situation and was not a "significant contribution factor" in Mr Capel's death.

Mrs Heath said her son was left in the psychotic state for nearly six hours after authorities were first called, giving him time to arm himself as his state worsened.

"It was totally mishandled from the first five minutes," Mrs Heath said. "Michael had no hope of getting any help.

"I wish I had never called the police and I cannot stress strongly enough [for other people] not to call the police. They were no help to me and no help to my son."

Both the NSW Police Force and Hunter New England Health indicated the recommendations would be carefully considered.