The Australian white supremacist who has admitted killing 51 worshippers at two New Zealand mosques has dismissed his lawyers and will represent himself when he is sentenced next month.

Brenton Harrison Tarrant, 29, pleaded guilty in March to 51 counts of murder, 40 counts of attempted murder and one count of terrorism following the attacks in Christchurch last year.

On Monday, his lawyers asked the High Court in Christchurch for permission to withdraw as Tarrant’s counsel, which they said he had requested.

The session was attended by some shooting survivors, with sentencing scheduled to begin on August 24 and running for up to three days.

Tarrant participated in Monday’s proceedings by video-link from jail in Auckland.

Justice Cameron Mander approved Tarrant’s request to dismiss his lawyers, saying he was satisfied he understood his right to legal representation and wished to waive that right.

A lawyer will still be appointed by the court to provide advice if Tarrant requests it.

The killing spree was the deadliest in New Zealand’s modern history and prompted the government to rush through new laws banning most semi-automatic weapons.

Tarrant was scheduled to go to trial over the charges in June. His change in plea came as a surprise and relief to survivors and relatives of the victims.