Survivors of Norway's worst massacre since World War II called on Thursday for the country to stand up against the hatred that motivated right-wing extremist Anders Behring Breivik's killing spree exactly 10 years ago.

Breivik set off a bomb near the government's headquarters in Oslo killing eight people before shooting dozens at a summer camp organised by the Labour Party's youth league (AUF) on the island of Utoya, leaving another 69 dead -- most of them teenagers.

"July 22 was not a random act. It was not a natural disaster," Astrid Eide Hoem, a survivor who has since become head of the AUF, said in a speech on Utoya Thursday afternoon.

Survivor Astrid Eide Hoem was 16 when a neo-Nazi set off a bomb in Oslo and then went on a shooting spree at a summer camp
Survivor Astrid Eide Hoem was 16 when a neo-Nazi set off a bomb in Oslo and then went on a shooting spree at a summer camp AFP / Petter BERNTSEN

"It was a targeted political terror attack, driven by an extremist right-wing ideology. By hate."

The shootings on the island lasted 72 minutes, as Breivik stalked and shot panicked young people trapped on the tiny island.

Eight people died in the car bombing of the government buildings in Oslo
Eight people died in the car bombing of the government buildings in Oslo SCANPIX NORWAY / POLICE / -

Breivik later said he had aimed to stage "a fireworks display" to draw attention to a 1,500-page anti-immigrant, anti-Marxist screed he dubbed a "manifesto" targeting those he blamed for ushering in the multiculturalism he abhorred.

"Ten years ago we travelled to Utoya to change the world. But then our world was changed forever," Eide Hoem said.

A third of the survivors of Breivik's massacre still suffer serious medical disorders
A third of the survivors of Breivik's massacre still suffer serious medical disorders AFP / JONATHAN NACKSTRAND

"The deadly racism and right-wing extremism live among us. Hate has killed before and hate can kill again."

The 26-year-old ended her speech with a call to action: "Now we must settle our accounts with racism and right-wing extremism. Every single day."

She and other survivors feel that even 10 years on Norway has still not truly faced up to the ideology that drove Breivik.

Ten years on, Utoya massacre survivors want Norway to confront far-right ideology
Ten years on, Utoya massacre survivors want Norway to confront far-right ideology AFPTV / Petter BERNTSEN

Speaking to survivors and relatives of the victims at a morning ceremony near the government complex where Breivik detonated his 950-kilogram homemade bomb, Prime Minister Erna Solberg urged empathy and tolerance.

"We must not let hate stand unopposed," Solberg said.

Church bells nationwide rang out in honour of the victims just after midday.

On the island Utoya, Breivik hunted down his 69 other victims, most of them teenagers
On the island Utoya, Breivik hunted down his 69 other victims, most of them teenagers AFP / Petter BERNTSEN

Shortly after the attacks, NATO chief Jens Stoltenberg -- who was Labour prime minister at the time -- promised to respond with "more democracy" and "more humanity".

"Ten years ago, we met hatred with love," Stoltenberg said in a speech during a church memorial service on Thursday.

"But the hatred is still present."

This week vandals scrawled "Breivik was right" on a memorial for Benjamin Hermansen, who was killed by neo-Nazis in 2001.

Stoltenberg also referenced the 2019 attempted attack by Philip Manshaus, who opened fire into a mosque on the outskirts of Oslo before being overpowered by worshippers.

The Norwegian intelligence service (PST) also warned this week the kind of ideas that drove the killings in 2011 were "still a driving force" for extremists at home and abroad.

"We have to admit that we as a society have not done nearly enough to see, to help, to carry the burden together, and to counteract the dark forces," Norway's King Harald said in speech Thursday evening during a memorial concert in Oslo, bookending the day's commemorations.

"It saddens me", he added.

Breivik, who is now 42, was sentenced to 21 years in prison but the sentence can be extended indefinitely.

"When you've been through something like this, you don't go back to being the person you were," Eide Hoem told AFP in an interview.

"I have trouble sleeping, I'm afraid, and I think I'll have to live with this all my life."

For some the pain is made worse by them still receiving threats and hate mail.

"I know that someone tried to kill me because of my beliefs," Elin L'Estrange, another survivor, told AFP.

"If someone today tells me that they want me dead, I take it very seriously," she added.