"If dealers or anyone else selling firearms has concerns about the legitimacy of someone who may approach them to buy firearms, they should contact police immediately.
"While at this stage there is nothing to suggest any wider threat to the public, we take any such illegal purchase seriously and will respond accordingly to ensure public safety."
The 'E, (MSSA)' endorsement on the licence enables licence holders to use military-style semi-automatic weapons.
The 'C, general' endorsement enables licence holders to collect pistols or restricted weapons, but does not allow the holder to fire the weapons.
Police say their inquiries into the matter are continuing.
In October last year, staff from the current affairs show Story forged a document to obtain a firearm, which they said was aimed at highlighting a loophole in the law.
Presenter Heather du Plessis-Allan broke the story, saying it showed a rifle could be purchased through mail order, apparently without producing a gun licence.
The mail order form sent to Gun City included false details, including an invented gun licence number.
A police investigation was started into allegations "false details had been used to fraudulently obtain a firearm via an online/mail order dealer".
During the investigation police searched Du Plessis-Allan's Wellington home.
Her husband, Newstalk ZB journalist Barry Soper, tweeted a photo at the time of police searching their home for handwriting samples.
But police decided not to charge Du Plessis-Allan and instead issued formal warnings against three MediaWorks staff for their involvement in the purchase of the firearm.
Police said they were satisfied the firearm was not purchased for any sinister purpose and that's why the investigation only resulted in the issuing of warnings.