Newshub has obtained an internal police document that shows a number of failures in the way police deal with firearms.
It shows their knowledge of the law around firearms is at an "unacceptable level", the licensing system is "no longer fit for purpose" and police and customs processes are "obsolete" and "leaving gaps".
Two women were shot dead on Wednesday by Whangarei man Quinn Patterson, who was amassed by an arsenal of illegal guns.
- Whangarei gunman barricaded house, stashed hand grenades and firearms inside
- Whangarei shooter 'planned to kill' - former workmate
- Whangarei shooting: Former landlord says fatal attack was 'out of the blue'
An admission by police chiefs in the internal report says that its approach to gun control is characterised by "ineffective and inconsistent decision making".
Paula Bennett's rejection of the gun law changes saw Police Association president Chris Cahill give her a public warning just six weeks ago.
"The consequences are going to be more firearms being stolen, more firearms in the hands of criminals and more people in New Zealand being shot," he said.
The report shows there are 242,000 firearms license holders, but police guess there's anywhere between 1.2 - 1.5 million guns.
While it may seem archaic to have a paper-based system, Ms Bennett says transferring to a digital database would cost 30 million dollars - and that's funding they just haven't got at the moment.