Brenton Tarrant, the Australian man convicted of killing 51 Muslim worshipers in New Zealand's deadliest mass shooting, told an appeals court he was not fit to plead guilty due to deteriorating mental health from harsh prison conditions. The self-declared white supremacist, who livestreamed the 2019 Christchurch mosque attacks on Facebook, is seeking to have his guilty pleas discarded and his life sentence without parole overturned.

Tarrant's appeal hearing, which began Monday in Wellington, will run for five days as a three-judge panel examines evidence about his mental state when he admitted to terrorism, murder, and attempted murder charges in March 2020. The 35-year-old appeared via video link from prison, where he was held in solitary confinement with limited reading material and contact with other prisoners. He claimed he suffered from "nervous exhaustion" and uncertainty about his identity and beliefs when he pleaded guilty.

Crown lawyers challenged Tarrant's claims, noting little evidence in prison documentation suggested serious mental illness. They pointed out he had access to legal advice throughout the process and could have requested trial delays or proceeded to trial. Tarrant admitted he had tried to mask signs of mental illness to appear confident. The appeal was filed two years late in September 2022, which Tarrant attributed to lack of access to required information.

The judges are expected to release their decision at a later date. If they reject his attempt to discard the guilty pleas, a separate hearing will address his bid to appeal the unprecedented life sentence without parole.