The National Party says it's been leaked documents of the Government's second round of firearms legislation, which will see compliance penalties increased 10-fold.
National's police spokesperson Brett Hudson says most of the new rules are a waste of police time.
"I'm worried about the path this Government is going down on gun reform," he said.
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"The fact yet another sensitive Government paper has been leaked to National suggests I'm not alone."
The leak is one of a number in 2019. In June, Education Minister Chris Hipkins confirmed National was leaked parts of a "draft" Cabinet paper about the tertiary sector.
It was the second time in two months National had been leaked a Cabinet paper. The party was leaked details of plans for the cannabis referendum in May.
Police Minister Stuart Nash said he won't comment in detail on the latest leak claims.
"What I would like to know is if the National Party is going to support what we're doing," Nash said on Wednesday.
"The final draft of the Bill has not yet been signed off by Cabinet so I will not comment on its precise contents."
Hudson claims the Government is going to increase many compliance penalties from $1000 to $10,000.
"It shows they don't believe this legislation naturally encourages compliance," Hudson said.
But Nash said the content of the Bill has already been well signalled. He said extensive details were released on July 22.
It's the second set of gun law changes - after banning military-style semi-automatic weapons and assault rifles - following the Christchurch terror attack on March 15.
It will now be enshrined in law that owning a gun in New Zealand is a "privilege", Nash said.