At the North Shore District Court today, Community Magistrate Dianne Hale said the charge related to possessing a semi-automatic shotgun.
Speaking outside court before his appearance, Tempero said he would fight the charges. He said the shotgun had been bought in Auckland with a licence.
He declined to comment outside after being released on bail.
According to the Celebrity Speakers' website, Tempero has been offering self-defence programmes at workplaces. The programme reportedly provides benefits in safety as well as being "inspirational''.
Tempero is due back in court next month.
The FBI is seeking to extradite his boss and three others to the US to face charges of conspiring to commit racketeering, conspiring to commit money laundering, copyright infringement, and aiding and abetting copyright infringement over the internet through the website Megaupload.
Two of Kim Dotcom's alleged co-offenders, Bram van der Kolk, 29, and Finn Batato, 38, were granted bail today although it could be a week until they are released because the police need to check the bail addresses.
The third alleged co-offender, Mathias Ortmann, 40, will continue his fight for bail in court tomorrow.