Finnish police has said they will monitor the Internet more rigorously for evidence of extremists plots following last week's twin massacres in neighbouring Norway.

Deputy police commissioner Robin Lardot said on Monday his forces will pay closer attention to fragmented pieces of information -- known as "weak signals" -- in case they connect to a credible terrorist threat.

He told public YLE radio that Finnish police previously enhanced their online surveillance after a 22-year-student gunned down 10 people at a vocational school in the central town of Kauhajoki in September 2008.

The gunman in the Kauhajoki shooting, who also killed himself, had dropped hints about his plans before carrying out the attack, as in the Norwegian case, Lardot said.

In both cases "the perpetrators had a need to say that they were preparing something like this," Lardot added.

Anders Behring Breivik, who has claimed responsibility for the Friday attacks in Norway that killed at least 76, was a member of a Swedish neo-Nazi Internet forum, according to Stockholm-based Expo foundation, which monitors far-right web activity.

Behring Breivik had posted on the Internet a 1,500-page manifesto prior carrying out the massive car bomb and subsequent mass shooting that killed 76 people.