After the ceremony, Stoltenberg addressed the criticism that Norway had focused too much on making sure the police and the military could respond better to a would-be terror threat in the future, rather than discuss the values of Breivik, who was jailed for life last year for killing 77 people.
"There is no conflict, we need both parts," Stoltenberg told the media. "(We need) both contingency and to make sure we have an open society, which does not provide a breeding ground for extremism,"
He added that he was keeping a watchful eye on right-wing populist developments across Europe, spurred on by what he called "desperation" in the current financial climate.
"We do not want to live in a closed society," Stoltenberg said.
He also addressed the detention in France last week by anti-terror police of a Norwegian neo-Nazi, felled for manslaughter in the early nineties.
"We have to distance ourselves from extremism regardless of a person's nationality or location. We should respect difference of opinions, but we should never accept when a person thinks that they are above the law, that they give themselves the right to take another's life in the name of their god, or their values. We should always condemn that," he said.
"The most important weapon against terrorism is our values, that we make sure to create a secure society."
At noon, the Crown Prince and Crown Princess will join Stoltenberg for a memorial service at Oslo Cathedral along with representatives for support groups that have tried to ferry Norway through its grieving for the 77 victims.
At 2pm, representatives will gather at Thorbjørn landing, on the mainland near Utøya Island, where Stoltenberg will address attendants and the media, before travelling over to the island to pay his respect to the victims who attended the Labour Party's youth wing summer camp two years ago.