Norwegian mass murderer Anders Behring Breivik made a Nazi salute when he returned to court today to argue that his isolation breaches human rights.

The right-wing extremist, who considered himself "to be 100 per cent Christian", killed 77 people in 2011 when he bombed central Oslo, killing ten people, before shooting 69 others on an island nearby, many of them teenagers attending a Labour youth camp.

The far right militant appeared in public for the first time since his 2012 trial, where he was sentenced to the maximum term of 21 years in prison, with possibility for extension.

In that time, he has had just one visitor, his mother, who was allowed into prison and gave him a hug shortly before she died of cancer in 2013.

Wearing a black suit, white shirt and golden tie, the 37-year-old raised his right arm in a Nazi salute as he arrived. 

Breivik will argue that his isolation in Skien jail violates a ban on "inhuman and degrading treatment" under the European Convention on Human Rights, as well as depriving him of a right to family life.

"He wants contact with other people," his lawyer, Oeystein Storrvik, told reporters before the trial.

The Attorney General of Oslo said there is no case to answer, saying in pre-trial documents: "there is no evidence that the plaintiff has physical or mental problems as a result of prison conditions".

In prison he has a three-room cell with a television and a computer but no Internet access. He is allowed out into a yard for exercise.

In a letter to Norwegian and Swedish media outlets, Breivik said he was kep in almost total isolation, only able to leave his cell for an hour a day. He said these conditions had forced him to drop out of a political science course he had been studying at the University of Oslo.

Norwegian authorities note that in a manifesto about his anti-Muslim views, Breivik wrote that "prisons are considered an ideal arena for which to recruit for political purposes."

Storrvik might take the case to the European Court of Human Rights if he fails in Norwegian courts.

Breivik considers himself a Christian, most explicitly described in the 1,500-page online manifesto he compiled over several months before his arrest.

"At the age of 15 I chose to be baptised [sic] and confirmed in the Norwegian State Church," the 32-year-old Breivik wrote. "I consider myself to be 100 percent Christian."

He identified as a cultural Christian, likening himself to a modern-day crusader, defending against "multiculturalism" and "Islamisation".

"Regarding my personal relationship with God, I guess I'm not an excessively religious man," he writes. "I am first and foremost a man of logic. However, I am a supporter of a monocultural Christian Europe."

Additional reporting by Reuters.