What you need to know

• Branton Tarrant stormed two mosques in Christchurch in 2019, killing 51 people
• Tarrant admitted to carrying out the shootings before being sentenced to life in jail
• Tarrant now says he wasn't able to make rational decisions at the time because of harsh detention conditions

A white supremacist who killed 51 worshippers at two mosques in New Zealand has launched an ‍appeal against his conviction and life sentence.

Branton Tarrant told an appeals court on Monday that he felt forced to admit to the crimes during this trial because of "irrationality" due to the conditions of his detention.

Tarrant said his mental health had deteriorated due to conditions in prison. He was held in solitary confinement, he said, with limited reading material or contact with other prisoners.

By the time he pleaded guilty, Tarrant said he was suffering from "nervous exhaustion" and uncertainty about his identity and beliefs.

Tarrant admitted charges of murder and terrorism

Tarrant ‌was ⁠convicted of 51 charges of murder, 40 counts of attempted murder and one charge ‍of committing a terrorist act.

He is serving a life sentence in prison without parole. It was the first time a New Zealand court had sentenced someone to life behind bars.

Tarrant, an Australian citizen, missed the formal time period to appeal, so he now needs the court's approval to proceed.

A panel of three judges is hearing the case at the Court of Appeal over five days.

Mosque killings shocked New Zealand

If Tarrant's appeal bid is successful, his case would return to court for a trial, which was averted when he admitted to the shootings.

A self-declared white supremacist, Tarrant stormed the mosques in Christchurch, New Zealand's second largest city, in March 2019.

He was armed with military-style semi-automatics, indiscriminately shooting at Muslims gathered for Friday prayers, livestreaming the killings ⁠on Facebook.

Those killed and injured were all Muslim and included children, women and the elderly.

It was the worst ‌mass shooting in New Zealand's history.

Edited by: Karl Sexton