Brenton Tarrant had earlier pleaded guilty to killing 51 people and injuring 40 others at the Al Noor Mosque and Linwood Islamic Centre in Christchurch on March 15, 2019.
Brenton Tarrant, who was sentenced to life for carrying out the 2019 mass killing in Christchurch, has claimed "his right to a fair trial was compromised" and may appeal the ruling.
Terrant’s newly appointed lawyer said on Monday that his client was "considering" filing a plea against the life sentence issued last year in August.
During his trial, Brenton Tarrant had pleaded guilty to killing 51 people and injuring 40 others at the Al Noor Mosque and Linwood Islamic Centre in Christchurch, New Zealand, on March 15, 2019.
"I advised my client to appeal his sentence and conviction," Tony Ellis told Radio New Zealand, claiming that Tarrant was "subject to inhumane or degrading treatment while on remand," which constituted a "breach of the Bill of Rights."
The lawyer made the claim in his communication with Chief Coroner Judge Deborah Marshall. A coronial inquiry will now be launched into the mass killing.
The lawyer also raised objections against the court not identifying Tarrant by his name in communications.
A relative of one mosque attack victim described Tarrant's claim as "seeking attention."
"Every now and again it's like there's some personality deficit where he just seeks more attention. It's like he's a narcissist, you know? He just enjoys that attention," Rosemary Omar was quoted as saying by Radio New Zealand.
Omar's 24-year-old son, Tariq, was among the victims of Tarrant's mass shooting at Al Noor Mosque.
Experts says it would be a monumental task for Tarrant to prove his claims.
Soon after Tarrant was sentenced, New Zealand's parliament passed new counter-terrorism legislation last year, granting more powers to security agencies in their efforts to fight terrorism.
The bill was part of a government move to implement the recommendation of a royal commission probe into Tarrant's terror attacks.
Under the law, security agencies will also have powers to enter, search, and monitor premises without a warrant.
Weapons or combat training for terrorist purposes was also criminalised, as was travelling to, from, or via New Zealand with the intent to carry out a terror offense.