Police are investigating a rash of fake submissions on an online form to hand in firearms which are being banned in the wake of the Christchurch mosque attacks.
The online form for owners to declare their intention to hand in guns was spammed with false notifications on Friday.
Some forms were reportedly submitted by gun lobbyists apparently trying to interfere with the process for handing in firearms.
Police blocked the online form to foreign users on Friday, and Assistant Commissioner Tusha Penny said the High Tech Crime Unit was investigating.
Ms Penny said in a statement that police restricted access to the forms to people in New Zealand only in an effort to prevent false forms being submitted.
"As the legislation changes apply to firearms in New Zealand, it is not expected there will be many people overseas who will be affected by these changes.
"Anybody overseas who has left a firearm they own in the secure storage and care of somebody in New Zealand is able to have that person act on their behalf."
Since the government moved to ban military-style semi-automatic weapons and assault rifles last Thursday, almost 1000 people had called the 0800 number for people wanting to hand in their guns and another 1000 have sent in a form. Police haven't said whether that number included any of the fake forms.
Ms Penny said police were making contact with people who have indicated they wish to hand in firearms.
"We remind people to please contact police before attempting to hand over their firearms. It is important people notify police so we can arrange a time to transfer the firearms safely into police care," Ms Penny said.
There are an estimated 1,500,000 guns in New Zealand and about 250,000 people hold firearms licences.