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."