Minister Shane Jones has been photographed firing a banned firearm while on holiday.

Jones was supposed to be studying the Cabinet Manual on his break last week. Instead, he was snapped shooting what appears to be an AR-15 - a weapon banned here by his own Government after it was used in the Christchurch terror attacks.

Photos posted to social media by his wife show him at an overseas firing range holding the weapon, NZME reports.

According to experts, the gun is an AR-15 - a lightweight semi-automatic rifle now illegal in New Zealand.

"It certainly looks like the firearm could be an AR-15 centre-fire rifle. If it is an AR-15 centre-fire rifle then the magazine looks, on the face of it, to be of high capacity," a spokesperson for the Council of Licenced Firearms Owners told NZME.

"That would mean both the firearm and magazine would be prohibited and now banned in New Zealand."

If the firearm was a .22 calibre, it would be banned, while the magazine could be legal.