He appeared on Monday (January 8) in a court set up in the gym of his prison, which is on the shore of a lake where the island of Utoeya, the site of Breivik's shooting spree, is also located.
Breivik sat impassively while his lawyer argued that 12 years of isolation had violated his human rights.
In earlier court hearings, he has argued isolation left him suicidal and dependent on anti-depressants.
Breivik killed eight people with a car bomb in Oslo then gunned down 69 others, most of them teenagers, at a Labour Party youth camp.
It was Norway's worst peacetime atrocity.
Breivik, who emailed out copies of a manifesto before his attacks setting out his theories, is suing the state and also asking the court to lift restrictions on his correspondence with the outside world.
His case has been a grim test for a country shaken to its core by the horror of his acts but which also prides itself on the rehabilitation efforts of its justice system.
Lawyers representing the justice ministry say Breivik must be kept apart from other inmates because he continues to pose a security threat.
And could still inspire others to commit acts of violence if he communicated with the outside world.
They point out he has contacts with guards, a priest and health professionals and sees two inmates for an hour every other week.
Breivik is serving a 21-year sentence - the longest a Norwegian court can impose - which can be extended for as long as he is deemed a threat to society.
Breivik also sued the state in 2016, arguing it was breaching the European Convention on Human Rights concerning torture or "inhuman or degrading treatment or punishment."
He won the case but it was overturned on appeal a year later.
In the new case, the judge's verdict - there is no jury - will be issued in the coming weeks.
