Norwegian police said on Wednesday they would interview a right-wing British blogger as they continue looking into whether anti-Islam zealot Anders Behring Breivik had help in the bomb and shooting attack that killed 77 people on July 22.

"He called us," police prosecutor Christian Hatlo told Reuters, referring to Paul Ray, a former leader of the anti-immigrant English Defence League and host of a website that publishes anti-Islamic ideas.

In his 1,500-page manifesto, Breivik described an unnamed Englishman as a source of inspiration, and many news organisations have sought out Ray for comment.

From his base in Malta, Ray has repeatedly denounced the attack and denied knowing the admitted killer, before deciding to travel to Norway to try to clear his name.

"For four weeks this has hung over my head like a black cloud, but I have heard nothing from the police," he told Norwegian newspaper VG. "I therefore decided to act myself."

Hatlo said Ray was "not a suspect" and said the police would decide after the questioning was complete whether to make any comment about it.

"We wanted to interview him because he is made out to be a mentor of Breivik in the manifesto," said Hatlo.

As a witness, he said, Ray is "in the same category" as an anti-Islamic Norwegian blogger known as "Fjordman" who was interviewed and released earlier this month.

He said investigators had turned up nothing to indicate anyone helped Breivik or knew about his plan to detonate a bomb outside the Norwegian prime minister's office and shoot down young Labour Party members at a summer camp.