By Charlotte Cook of RNZ

A soldier has been arrested at Linton Military camp, amid suspicion they are part of a far-right extremist group.

The Defence Force has yet to confirm what, if any charges the soldier is facing.

But the arrest has raised concerns far-right groups could be infiltrating New Zealand's military.

The extremist, Christian body-building group, Wargus Christi had claimed online that the arrested soldier was part of their organisation.

In an internet chat room, members spoke about how the man was removed from the group after news of an investigation.

Another hoped their "brother" was going to be okay.

A Defence Force spokesperson confirmed the arrest.

"There was a cordon in place in part of the Linton Housing Area attached to Linton Military Camp on Friday. New Zealand police executed a search warrant and one soldier was taken into military custody."

They said no further details were able to be released because of an ongoing criminal investigation with police.

RNZ was told there would be one-on-one monitoring of the soldier at all times.

Activist group Auckland Peace Action said infiltration through defence and police forces was a common and proven tactic for right-wing groups.

Spokeswoman Valerie Morse said the military could be a breeding ground for anti-Muslim behaviour.

"The whole mindset of the military has effectively been about criminalising Muslims for at least the last 20 years," she said.

It was alarming that Wargus Christi's ethos of blood, honour and brotherhood could be permeating New Zealand's military, Morse said.

Massey University's Professor Paul Spoonley, who has studied the far-right and anti-Semitic movements, said he had seen people in the armed forces with an online presence, but believed the numbers were limited.

"There appear to be people who are in the Defence Force who contribute to online discussions.

"I've certainly been concerned through this year at some of the comments that I've seen which appear to come from Defence Force personnel which are really very anti-Muslim, and anti-Semitic."

Minister of Defence Ron Mark would not confirm if the soldier who is in custody was on their radar. Photo / Mark Mitchell

The Defence Force attracted people who were interested in far-right ideals, Spoonley said.

"I think there's a bit of an issue that the Defence Force tends to attract people who might be sympathetic to those views but the Defence Force itself has been working very hard to make sure that it is not a recruiting ground or a breeding ground for far-right extremists."

He said Wargus Christi's focus on bodybuilding was connected to their alt-right, white, Western, anti-Semitic views.

"This thing about body-building, about keeping the body pure for the fight, that's about how it appears at first instance to be something about making your body stronger and better.

"But then the reasons for that are because you want to be able to fight the fight when it then comes and you want to be able to fight against the people that are out to destroy your society," he said.

Minister of Defence Ron Mark would not confirm if the soldier who is in custody was on their radar.

"What I take strength and confidence in is that this has happened and the military are clearly very observant, doing their job.

"I'd like to think that any government department that has the security and interests of this nation at heart would be monitoring itself as well."

It was unclear if the man would go through the judicial system, or the military court martial process.