Breivik, a far-right extremist, killed 77 people in Norway's worst peacetime atrocity in July 2011. He killed eight with a car bomb in Oslo and then gunned down 69, most of them teenagers, at a Labour Party youth camp.

With a shaven head and dressed in a dark suit, Breivik made a white supremacist sign with his fingers before raising his right arm in a Nazi salute to signal his far-right ideology as he entered the court.

He also carried signs, printed in English, including one that said "Stop your genocide against our white nations" and "Nazi-Civil-War".

Addressing the judge, Breivik described himself as a parliamentary candidate.

Breivik, now 42, is serving Norway's maximum sentence of 21 years, which can be extended indefinitely if he is deemed a continued threat to society.

The Telemark court in Skien, southwest of the capital, where Breivik is serving his sentence, will hear the case this week after the Oslo state prosecutor's office last year rejected Breivik's application for early release.

"Our position is that it is necessary with (continued) confinement to protect society," the prosecutor in charge, Hulda Karlsdottir, told Reuters ahead of the hearing.

Proceedings will take place over a maximum of four days in a prison gymnasium converted into a makeshift courtroom, with a decision expected about a week later.

If his request for release is denied, Breivik, who has changed his legal name to Fjotolf Hansen, can apply for a new probation hearing in a year's time, Karlsdottir said.

Breivik lost a human rights case in 2017 when an appeals court overturned the decision of a lower court that his near-isolation in a three-room cell was inhumane.

The European Court of Human Rights rejected a subsequent appeal.

Australian Associated Press