Winston Peters unloads on Shane Jones' critics over AR-15 photo

New Zealand First leader Winston Peters has opened fire against "unreconstructed morons" after Shane Jones was photographed using a banned gun.

On Monday, it was revealed that during his overseas holiday, Jones shot an AR-15 - a weapon banned here by his own Government after it was used in the Christchurch terror attacks.

Questioned about the photos at her post-Cabinet press conference on Monday, Prime Minister Jacinda Ardern said she "absolutely" would not have fired the gun and she would raise this with Jones.

However Peters is defending Jones, telling Magic Talk host Peter Williams that his MP was just having fun "like most people do".

"The answer is, he was on holiday, yes. He walked into a place that offered those services and am I happy with that? Yes I am," Peters said.

"What I am not prepared to do though is standby with a whole lot of hopeless ne'er-do well critics who don't seem to have a life criticise someone for actually having a life."

Earlier on Tuesday, Politik political journalist Richard Harman said Jones was "dog-whistling to those who have little time for metropolitan political correctness".

"The Prime Minister may express her abhorrence at the picture, but it looked like a wink and a nod that could well resonate among the many gun owners frustrated with the Government's gun clampdown," he wrote in an article.

Questioned by Williams on this point, Peters responded to Harman with a brutal put-down.

"You've got some unreconstructed morons in your profession and that's one of them," he said.

"You go away on holiday and have a break and do unusual and different things and to impute anything else is sheer bulldust."