Concerns mosque attacker Brenton Tarrant's appeal will provides him with a platform to spread more of his violent and dark points of view

The terrorist is seeking to overturn his guilty pleas to 51 counts of murder, 40 counts of attempted murder, and one count of terrorism.

A week-long hearing in Wellington will consider whether his prison conditions affected his ability to plead.

Sara Qasem - whose father died in the attack - has told TVNZ it's jarring to see him appear again.

But she says he doesn't have the power to worry her - because her love far outweighs her fear.