Police figures showed that the number has increased from 21,000 in 2014 to 34,000 this year, Radio New Zealand reported.
The figures revealed there were 12,000 more applications for gun licences processed this year compared to last year.
Police attribute the increase also to a 10-year cycle of licence renewals, which are now due.
The renewals are likely to reach a peak of 50,000 next year.
Firearms safety consultant Nicole McKee said regardless of whether people were renewing or applying for new licences, they should be safety-conscious as there had also been an increase in hunting accidents.
"Last year, we had five non-intentional incidents with one death. In 2013, we had five non-intentional incidents with one death. So far this year, we're up to 13 now with six deaths."
McKee said there were about 230,000 licensed firearms owners in the country and police estimated there were about 1.5 million guns.