Christchurch terror attack: Inside alleged gunman's maximum security prison

These are the insides of the maximum security prison where the alleged Christchurch gunman is believed to be held.

Corrections won't confirm the details, but it's understood the 28-year-old Australian man suspected of killing 50 people at two Christchurch mosques on March 15 is being held at Auckland Prison in Paremoremo.

Newshub went to the prison when it opened in 2018. It's home to some of New Zealand's most-hardened criminals, and built like a fortress to prevent them from escaping.

The building is surrounded by a web of wire to prevent breakouts and comes with heartbeat detectors at the entry area.

Security measures are equally strong inside. The walls are made of massive concrete blocks weighing 17kg each, and the beds are built into the walls.

Prisoners are under constant monitoring via cameras and dome reflectors.

"The prisoner we deal with today is a much more hardened prisoner than we dealt with 20 to 30 years ago. Many people don't respect authority, they don't even respect themselves," Corrections CEO Ray Smith told Newshub in 2018.

The entire facility is a single storey, because escorting prisoners on stairs is highly dangerous, and there's more space for officers to regain control of a situation.

"It's very hard in the old facility, there's a lot of moving of people around - you can't even shower in your own cell, which means you're always moving people who are volatile and unsettled," Smith said.

And it appears the alleged gunman isn't enjoying his stay at his new residence.

Stuff reports he's laid a complaint because he's being denied visitors and phone calls, in contravention of the Corrections Act.

"He doesn't get the usual minimum entitlements. So no phone calls and no visits," the source told Stuff.

Corrections told Newshub in a short statement he was "being 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."

Newshub has asked Corrections for more detail about his treatment and the report he's filed a complaint.

"For operational security reasons no further information will be provided," Corrections said.

Newshub.