Gun owners are warning the cash earmarked in the Budget for the firearms buyback scheme is woefully inadequate.

Photo: RNZ / Ana Tovey

The government has set aside $150 million to compensate gunowners for certain types of semi-automatic firearms and parts banned in the wake of the Christchurch mosque shootings.

However, Nicole McKee from the Council of Licensed Firearms Owners said a fairer compensation figure would be "over a billion dollars".

"It would appear that the decimal point might be in the wrong place. The council is preparing calculations themselves based on feedback from some of the dealers, and it appears the government is pretty light on what the costs might be."

Gun owners were being punished for the actions of "a foreign terrorist", she said.

"They have not done anything wrong, this is their personal property. So fair just and reasonable pricing should be acknowledged by government. And quite frankly, $150 million is not going to cut it."

If the government tried to do the buyback scheme on the cheap, there was a risk it could backfire, Ms McKee said.

Costing also needed to reflect the infrastructure and security for the collection and destruction of firearms, she said.

The Budget includes $5m for operating costs.

Ms McKee said MPs were warned by Australian authorities during the select committee hearing against trying to cut costs.

"The danger is people will not hand in their firearms if the price is not there."

Ms McKee said she was not suggesting illegal firearms could "go underground", but gun owners could attempt to transfer them to collectors' licenses or mount a legal challenge.

"It's not the first time in New Zealand that future government have had to pay the price for unfair settlements."