Independent advisors will develop a price list for New Zealand's gun buyback scheme, as new firearms laws are expected to come into force this week.
High capacity magazines and parts will be included in compensation.
The buyback comes as part of the proposed gun law changes that were spurred after the Christchurch terrorist attack that killed 50 people on March 15.
The Government banned semi-automatic weapons and assault rifles after the attack.
Police Minister Stuart Nash said proposed change to the Arms Amendment Bill "will create a framework to set compensation based on make, model and condition of the items".
"Independent advisors will develop the price list for approval by Cabinet. A separate expert panel of advisors will be established to determine fair compensation for high value firearms."
The cost of the buyback scheme could go as high as $300 million, deputy Prime Minister Winston Peters said recently.
Mr Nash said police consulted with Australian officials to look at legal risks that were encountered since its buyback scheme was introduced after the Port Arthur massacre.
"The new measures make it clear that surrendered firearms will be the property of the Crown. Owners will be compensated for them, if the guns were lawfully obtained and the person had the appropriate firearms licence. Price lists will be set out in regulations which are now being drafted," Mr Nash said.
He said the framework intends to provide certainty around the buy back.
"Police are already collecting bank account details from people who are taking part in the gun amnesty. They are well placed to begin paying compensation once the scheme is confirmed. I can reassure firearms owners there will be plenty of time for them to hand over their weapons as part of the amnesty and to have their compensation processed under the buyback as well."
The amnesty period is set for September 30, however Mr Nash said that "if necessary, the amnesty can be extended by a month or so to run alongside the buyback".