Norwegian mass killer Anders Behring Breivik has told a court his twin attacks, which killed 77 people, were "sophisticated and spectacular" and he would do them again.

On the second day of his trial, Breivik took the stand for the first time after one of the trial's five judges was dismissed for posting an online comment saying the 33-year-old gunman should face the death penalty.

Breivik has pleaded not guilty and said he was defending his country by setting off a car bomb that killed eight people at government headquarters in Oslo last July, then killing another 69 people in a shooting spree at a youth summer camp organised by the ruling Labour Party.

"I have carried out the most sophisticated and spectacular political attack committed in Europe since the Second World War," Breivik told the court in a 73-minute prepared statement.

"They (Norwegians) risk being a minority in their own capital in their own country in the future.

"Yes, I would have done it again, because offences against my people ... are many times as bad."

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Speaking in a calm and composed voice as he presented his Islamophobic and anti-immigration ideology, Breivik described Oslo as a "multicultural hell".

He said the victims of his attacks were "collateral damage" in his war against multiculturalism.

"People who call me evil have misunderstood the difference between evil and brutal," he said, adding that the US's World War II decision to drop nuclear bombs on Japan was, like his carnage, also made with "good intentions."

"I acted out of goodness, not evil."

He told the court his actions were cruel, but necessary.

His hour-and-a-half statement touched on the Roman invasion of Britain and Bolivian indigenous autonomy.

The judge ordered him to wrap up five times, but Breivik said his full statement was "essential" to explain his actions.

Some in the court yawned, others sniggered.

The statement was not televised as many Norwegians feared he would use the dock as a pulpit for his corrosive ideology.

Tears for 'dying' country

On Monday, prosecutors screened a 12-minute Islamophobic video made by Breivik and broadcast on the internet on the day of the attacks, featuring photos of Islamists set to soft music.

The 33-year-old extremist, who opposes Norway's generous immigration policies, welled up in tears as the video played.

Asked by the prosecutor on Tuesday why he had cried, he responded: "Because my country is in the process of dying - it was the sorrow over seeing my country ... deconstructed."

It was "especially the songs, combined with the message" that brought tears to his eyes, he said, adding: "It was my first YouTube video."

While he has admitted the killings and will likely be kept behind bars for the rest of his life, Breivik's main objective is to prove he is sane, a court judgement that he sees as vindicating his anti-Muslim and anti-immigration cause.

The high school dropout has said being labelled insane would be a "fate worse than death".

If found guilty and sane, Breivik faces a maximum 21-year sentence but could be held indefinitely if he is considered a continuing danger.

If declared insane, he would be held in a psychiatric institution indefinitely with periodic reviews.

Norway does not have the death penalty.

Judge sacked

Thomas Indreboe posted an online comment saying Breivik should get the death penalty. ( Reuters: Hakon Mosvold Larsen )

The day began in controversy after the court dismissed a lay judge after he posted a comment on a Facebook page days after the massacre saying the gunman should face the death penalty.

Two professional judges, as well as three lay judges chosen from civil society, preside over the court.

Lay judge Thomas Indreboe posted "The death penalty is the only just outcome of this case" on a Facebook page.

After a 30-minute recess to reach a decision, chief judge Wenche Elizabeth Arntzen said Mr Indreboe was unfit to continue because of the comments.

He will be replaced by one of two substitute judges already in court.

On Monday, Breivik appeared for the first time in court, giving a clenched-fist salute, smirking at the court and pleading not guilty in a trial that threatens to showcase his anti-Islamic views.

Breivik listened impassively for hours on the first day of the trial as prosecutors read out an indictment detailing how he massacred teenagers trapped on a island resort outside Oslo.

During the attacks, Breivik shot most of his victims several times, often using the first shot to take down his target then following up with a shot to the head. His youngest victim was 14. He later surrendered as "commander of the Norwegian resistance movement".

Public platform

More than 200 people sat in the specially built courtroom while about 700 attack survivors and family members of victims watched on closed-circuit video around the country.

One survivor said it was difficult knowing he was breathing the same air as his tormentor.

"This man who killed very many of my friends and he tried to kill me. But at the same time it's good to see him in this position because he's very reduced from where he was at Utoya," he said.

"He can't harm me any more."

Some Norwegians fear Breivik will succeed in turning the trial, with about 800 journalists on hand, into a platform for his anti-immigrant ideas.

One Norwegian newspaper offered online readers a way to remove all Breivik-related stories.

His defence team has called 29 witnesses to argue Breivik was sane, with a world view shared by a narrow group of people.

His proposed witnesses include Mullah Krekar, the Kurdish founder of Islamist group Ansar al-Islam, who was recently jailed in Norway for making death threats, and "Fjordman", a right-wing blogger who influenced Breivik.

Breivik is scheduled to testify for about a week.

An initial psychiatric evaluation concluded that Breivik was criminally insane while a second, completed in the past week, found no evidence of psychosis.

Resolving this conflict could be the five-judge panel's major decision during the trial.

The trial is scheduled to last 10 weeks.

ABC/wires