A number of gun owners have voluntarily given up their semi-automatic rifles in the wake of the Christchurch terror attack.

Farmer and former Green Party candidate, John Hart, is one of them.

Hart told Mike Hosking it has taken Friday's tragedy for farmers to question why they have the rifles in the country at all.

"I've had a lot of interesting feedback from farmers who feel exactly the same way. They maybe haven't gone to that step yet [getting rid of their guns] but they can see the need for some sort of restriction or ban."

He said giving up his gun was easy for him because it would help make New Zealand safer.

"I'm basically just living my values. Once I decided that the country was going to be better off without this category of firearm, I couldn't in all conscience keep my own one."

When asked how he would have defended having a semi-automatic gun in the past, Hart said he would've said, "it's not a big deal". However, that all changed for him after the Christchurch terror attack.

"Lots of rural people use semi-automatic weapons and I hadn't really made the connection, I guess it took Friday's tragedy for us to really think about what it means to have these weapons in the country at all."

While he did use semi-automatic weapons for hunting, he said they aren't a necessity.

"There's no question that in some cases there is a legitimate use for these things, but that being said there are other ways of achieving the same goal in 99 per cent of cases."

Hart said now is the time to take action.

"It a real shame that it does take these sorts of tragedies for us to galvanise into action, but that doesn't take away from the need to do it and if we have got the opportunity now where people are actually thinking about it more seriously, let's do it."