Mr Dimery said police leadership needed to take better care of front line officers to make sure police continued producing reductions in crime.
"Look after the front line staff and look after your staff, they will continue to do the outstanding job they have always done."
Mr Dimery said he had been "outspoken" about his problems with police organisation throughout his career.
"I think the last straw I think was just realisation to myself that what I was doing wasn't making a difference."
However, the Commissioner of Police, Peter Marshall, rejected Mr Dimery's claims, saying the New Zealand Police is "neither a force or a business".
"It is a service and a highly regarded one at that, being run in a business-like fashion," Mr Marshall said.
He said the police are "good value for the $1.4 billion of hard-earned taxpayers money invested in the organisation".
"Recent surveys show we are riding high in terms of public trust, confidence and satisfaction," Mr Marshall said.
"Most police recognise that NZ Police is one of very few public agencies that has not had a cut to its budget. Our budget this year remains unchanged from that of last year," said Mr Marshall.
"As for resourcing, the Northland District has the second highest ratio of police per population ratio in New Zealand, second only to Eastern district."
Mr Marshall pointed to a 10.5 percent drop in crime in the Northland police district.
He also stressed policing is an "innately dangerous and difficult job".
"New Zealand Police officers, through their dealing with uncertainty and volatile situations serve the people of this country extremely well. In no way, shape or any form would I want any of my comments to be interpreted as watering down the difficulty of the role."
He said over the past year some 14 of the 43 Area Commanders had moved for a variety of reasons.
"Refreshment and rejuvenation in an organisation with extremely low attrition (running at 3 percent per annum) is no bad thing. I have been impressed with the realism that nearly all my commanders have had in terms of whether or not they see themselves as having the energy, enthusiasm and skills to take the organisation forward in the challenging environment we are in."