Brenton Tarrant, charged for murder in relation to the mosque attacks, is seen in the dock during his appearance in the Christchurch District Court, New Zealand March 16, 2019. Photo: Mark Mitchell/New Zealand Herald/Pool via REUTERS.

Wellington - The suspected Australian white supremacist who opened fire on worshippers in two mosques in Christchurch earlier this month, killing 50 people, has reportedly lodged a complaint over prison conditions.

According to New Zealand media reports, the 28-year-old has lodged a formal complaint about his rights in prison.

A Corrections source told the news website Stuff that the prisoner complained he was being denied access to visitors and phone calls from his cell in an Auckland prison.

A Corrections spokesperson did neither deny nor confirm the claim but told dpa on Sunday he was "managed in accordance with the provisions set out in the Corrections Act 2004 and our international obligations for the treatment of prisoners."

"At this time he has no access to television, radio or newspapers and no approved visitors," the spokesperson added. "For operational security reasons no further information will be provided."

The suspect is held in Auckland's Paremoremo Prison on the North Island, the country's only high security unit after he was flown there from Christchurch by the New Zealand Defence Force.

The 28-year-old was remanded in custody and is set to reappear at the High Court in Christchurch on April 5. It is likely that he will remain in Auckland and will appear in court via audio-visual link. He has rejected a duty lawyer and said he would represent himself in court.

At his first court appearance one day after the attack he was charged with one count of murder but further charges are expected to be added at his next appearance.

Police have not yet confirmed if he would face any terrorism-related charges.

There are concerns that he will use his trial as a platform to broadcast his white supremacist beliefs, in a manner similar to Anders Breivik, the Norwegian right-wing terrorist who murdered 77 people in 2011.

Breivik has also complained about his treatment in prison. In 2018 the European Court of Human Rights rejected Breivik's appeal who had complained that his prison conditions were akin to "inhuman or degrading torture.