New Zealand Mosque Attacker Sentencing to Begin on August 24

Brenton Tarrant pleaded guilty earlier this year to 51 charges of murder, 40 charges of attempted murder and one charge of committing a "terrorist act".

Justice Cameron Mander said the hearing is estimated to last three days, but it will take as long as is necessary.

Tarrant has been in police custody since March 15, 2019, when he was arrested and accused of using semiautomatic weapons to target Muslims attending Friday prayers at two mosques in the South Island city of Christchurch.

The attack was streamed live on Facebook and cited as providing inspiration for several other attacks targeting religious groups around the world.

Tarrant had planned to fight the charges but changed his plea to guilty in March this year.

Justice Mander said arrangements will be made to allow victims and family members currently based overseas, and unable to travel to New Zealand, to view the sentencing remotely.

New Zealand borders remain shut for foreigners, and New Zealanders returning will have to stay in quarantine for 14 days, as the government looks to limit the spread of the coronavirus pandemic.

Tarrant's remand was extended to find a suitable date after all COVID-19 restrictions were lifted.

However, waiting for changes to border controls will likely result in a very extended period of delay, Justice Mander said.

"Finality and closure are considered by some as the best means of bringing relief to the Muslim community," he said.