Racist white male terrorists a rising global problem - expert

In the wake of Friday's massacre in Christchurch, the issue of white supremacists is on the public's mind.

When a 50th death was announced yesterday, it made the Christchurch attack the eighth worst mass shooting in global history, and a rising number of attacks are being carried out by racist white men.

When he was standing in court, Brenton Tarrant did a hand signal associated with white supremacists.

It suggests he belongs to a growing number of white men accused of mass killings.

Since 1982, the majority of mass shootings in the United Stated have been committed by them.

Gang expert Jarrod Gilbert says it's a rising global problem.

"I think in the past we have probably been guilty on focusing our attention on what we might consider the usual suspects and ignoring what has been a genuine threat."

In less than a decade, there have been at least 15 terror attacks linked to white supremacists.

In 2011, Anders Brevik killed 77 in Norway, targeting youths he saw as supporters of multiculturalism.

Four years later Dylann Roof killed 9 people in a black church in South Carolina. He wanted to trigger a race war.

And late last year a white anti-Semite shot dead 11 Jews at a synagogue in Pennsylvania.

Now after the attack in Christchurch, New Zealand is taking the issue of white supremacists much more seriously.

Gilbert says it's impossible to tell how many there are.

"They have traditionally existed in small pockets, in small gangs and they've tended to be in the South Island."

Most of us think of white supremacists as the traditional "skinheads", but they're quite different to the "alt right", with which Gilbert associates Brenton Tarrant.

The alt right are the social media-savvy types like controversial blogger Milos Yiannopoulos, whose visa to Australia was cancelled after comments he made about the Christchurch massacre.

"The alt-right tends to be more quasi-intellectual at least more engaged in their philosophical underpinnings as they evil as they are and they tend to be more international so they don't hang out on street corners they tend to exist online," says Gilbert.

In 2016, former Pantera heavy metal band member Phil Anselmo caused controvorsy after he yelled "white power" at a gig.

He's due to arrive to play in New Zealand next week, but Kiwi musicians have asked his new band not to play.

Musician Tom Anderson said Anselmo needs to own up to his actions.

"They should not unless they come out and make a full statement denouncing their past actions and the actions that happened on Friday."

The band says it doesn't support white supremacy and will make a decision whether or not to cancel the tour within the next 48 hours.

This time last week, their presence probably wouldn't have been a problem,  now it's a different story.