A Department of Labour Inspector has criticised the way police carried out a drug search at the home of Napier gunman Jan Molenaar.
Paul West told an inquest in Napier on Wednesday the officers who carried out the search warrant contravened several police regulations.
The inquest is into the deaths of Senior Constable Len Snee and Molenaar in Napier in May last year.
At the start of a 50-hour siege on Hospital Hill, Molenaar shot Mr Snee dead and severely wounded his two colleagues and a member of the public.
The next day the 51-year-old gunman shot himself.
The three police officers were searching for drugs at the Napier house when the owner, Molenaar, arrived home.
Mr West told the inquest the fact that the officers did not wear protective vests and that their drug search was casual, suggests there may be a national problem with police.
But Superintendent Tony McLeod says that is not the case and the response by Molenaar was disporportionate to his drug offences.
Mr West recommends police headquarters consider reviewing the adequacy of their systems and their organisational culture in at least three areas.
Molenaar's notes made public
The contents of notes that Napier gunman Jan Molenaar wrote just before he died have been made public for the first time.
After Molenaar's former partner Delwyn Keefe gave evidence on Tuesday, Coroner David Crerar read out the two notes .
In one he said he was bad, he let everyone down and paid for his crime.
The other, written specifically to Ms Keefe, said that he loved her, she was a loyal, faithful good person and that he had done his best to make her happy.
Detective Superintendent Rod Drew, who oversaw the siege, says it could have been prevented if associates of the gunman had spoken up earlier about Molenaar's mental state and his large store of illegal weapons.