Right-wing extremist Anders Behring Breivik, who murdered 77 people in Norway's worses peace-time killing in 2011, has applied for parole, his lawyer said Wednesday.

Breivik also plans to file a new lawsuit against the Norwegian state regarding his conditions in prison, where he is kept apart from other inmates, lawyer Oystein Storrvik said.

In July 2011, disguised as a police officer, Breivik tracked and gunned down 69 people, most of them teenagers, at a Labour Party youth camp on the island of Utoya, shortly after killing eight people in a bombing outside a government building in Oslo.

He was jailed in 2012 to Norway's then-harshest sentence, 21 years in prison which can be extended indefinitely.

"In his name I have sent in a request for parole," Storrvik told daily newspaper Verdens Gang.

Norwegian Anders Behring Breivik gunned down 69 people at a youth camp on the island of Utoya, shortly after killing eight people in a bombing outside a government building in Oslo in 2011
Norwegian Anders Behring Breivik gunned down 69 people at a youth camp on the island of Utoya, shortly after killing eight people in a bombing outside a government building in Oslo in 2011 NTB Scanpix / Lise AASERUD

"He has the right to a legal review for parole at the end of the minimum period, which is 10 years in his case. It's a right all convicts ... have and that he wants to exercise," he said.

The lawyer also said Breivik plans to file another lawsuit against Norway to protest against "such a long period of isolation" in prison.

Breivik has previously filed a lawsuit against the state over his prison conditions, which he said were in breach of the European Convention on Human Rights barring "inhumane" and "degrading" treatment.

After winning a partial legal victory in 2016, he has since been rebuffed by Norway's higher courts and the European Court of Human Rights.

In Skien prison, Breivik has three cells each measuring 10 square meters (107 square feet), with outdoor views outdoors, and he can exercise, play video games and watch television.

A support group for families of the victims contacted by AFP had no comment on his parole request.