Police have processed at least one firearms licence in less than a day, according to figures obtained through the Official Information Act.
The figures also reveal that 96.29 percent of applicants succeeded in getting a licence in 2017 and 2018, with just 0.54 percent refused.
Police received 67,098 standard firearms licence applications in the two years and approved 64,612 of them.
Only 359 applications were refused and police said the rest were either still under consideration or had been withdrawn by the applicant.
While the success rate was causing some angst for people wanting stricter gun control, it was the length of time some licences were taking to be approved that was causing the most concern.
Police refused an interview with RNZ, but in a statement, that it was likely that any licence recorded as being approved on the same day it was applied for was the result of a processing error.
"All New Zealand firearms forms are currently paper based and then entered into [the] police computer system," the statement read.
"It is likely that where our system shows one day for an application to be considered and approved, that was due to an inputting error of the start date and the end date at the time it was entered into the system."
RNZ asked police if it was certain that a processing error had been made.
Deputy Commissioner Mike Clement did not address the specific licence, but said all applications take a reasonable amount of time to process.
"They require referee interviews, vetting checks, security checks, and administrative processing," Mr Clement said. "All of these requirements take time."
Mr Clement said the current paper based application process was clunky, and could mean it sometimes looked like a licence was handed out in one day.
"While that isn't the preferred approach, it does happen and indicates the need for a better technology enabled system," Mr Clement said.
"This is why police is working hard to modernise our delivery of firearms services, including moving to online licensing - which will have its capability thoroughly tested first."
Gun Control NZ, the newly formed group lobbying for stricter firearms laws and the introduction of a gun register, is concerned about the numbers.
Spokesperson Nik Green said he hoped the police made a processing error, rather than a gun licensing one.
"That would be very worrying," Mr Green said.
"The way that the process has been described to us is that, a renewal is the same as a new application. You have to go through all of the same checks and all of the same interviews, so to do it in one day seems implausible.
"I would have to assume that it was a mistake of some kind."
The information provided by the police, obtained under the Official Information Act, showed the longest time it took to approve a licence was 711 days.
Success rates a concern
Joe Green is the former head of firearms control at the police and said he too expected the police had made a processing error when it came to issuing a licence in one day.
But the other figures including the high success rates for those applying for licences were to be expected.
"What happens is the fact that we have a licensing regime, acts as a hurdle," Mr Green said.
"People who think that they may not be likely to get a firearms licence are unlikely to apply, which means that you do end up with a very low level of refusal."
But Gun Control's Mr Green said the application process may need to get tougher.
"It is surprisingly low, isn't it. You think about other licensing regimes, you tend to have higher refusal rates.
"I think it prompts some questions about whether we're asking tough enough questions."
During 2017 and 2018, it took an average of 46 days for police to approve a gun licence.
Police aimed to complete a licence in 30 days, they said.
Joe Green said despite not meeting their target, police did a good job in that respect.
"Well given that police report for that year, in their Annual Report, that they reduced resources to that area due to other priorities, that's actually a very good performance," Joe Green said.
"The fact that they're doing that in a six week period is well done."
He said the quality of the vetting process was a separate measure, and he hoped police were not taking shortcuts in order to speed up the licensing process.
Police said they had approximately 72 full time staff members working on gun licensing, and 260 vetters working on an as required basis.