Police Minister Stuart Nash has no intention of resigning over the gun buyback data breach, he says.
Police have admitted personal information about gun owners, such addresses and dates of birth, was available to 66 firearms dealers through its gun buyback website.
They say only one person looked at the data, though the Council of Licenced Firearm Owners (COLFO) insists at least 19 people accessed sensitive information.
Police say the breach occurred after private German company SAP did an unauthorised software update.
Police Minister Stuart Nash said that was where the responsibility lay.
"I'm not going to resign on this, there's a whole lot of work to do and I want to see the job done."
He continued to receive assurances from SAP, via the police, that only one person had viewed the data, he said.
"If in fact COLFO have other information, I'd love them to get in touch with the police and work closely with them."
In a subsequent statement, police said a system audit by vendors over the past day had confirmed only one Logan by a dealer with legitimate access was made.
The dealer confirmed that the information they accessed was not used in anyway, police said.
Police said they'd requested information from COLFO in regards to their claims but nothing had been provided so far.
Information accessed included the names, addresses, contact numbers, firearms licence numbers, and bank account details of 35 people, while less than 500 people had their names and addresses accessed.
"Today we will be calling the 35 people who have had their full details accessed to inform them of the privacy breach, provide advice on what they can do to ensure the ongoing security of their information and answer any questions they may have," said Deputy Commissioner Mike Clement.
The people involved in the other group, who had their name and address accessed, would also be contacted, police said.
"Anyone who has concerns in regard to the security of their firearms as a result of this privacy breach can call 0800 311 311 and speak with our staff about how the firearms can be handed over to police."
Police said the online notification platform, which was shut down yesterday, would remain offline until they were sure the system was secure.
National leader Simon Bridges said there were still questions about whether ministers were "still right" to keep talking about only one person accessing the data.
"It seems to me ... the police can't even say that, obviously COLFO is saying something different as well - there's just a failure to answer basic questions."
The buck stopped with Mr Nash and Prime Minister Jacinda Ardern, Mr Bridges said.
"A Prime Minister who's trying to wash her hands 'it's not us this is SAP' - well, it is her, this was a signature issue for her and for the police minister."
He said the buyback had already been a fiasco, and this would seriously compromise public trust in the scheme.