Norway has seen increased Russian naval activity off its coast, paralleling higher activity by its air force and another sign of the Kremlin's greater military assertiveness, a senior Norwegian defence official said.

Nato member Norway, which borders on Russia in the Arctic, has repeatedly scrambled fighters in past months to observe Russian bombers on exercises along its coast and into the North Sea, in a repeat of Cold War tactics used by the Soviet Union.

"We have seen an increase in Russian maritime activity," Deputy Defence Minister Espen Barth Eide said.

"We see some of the same pattern as we have seen with the flights - that Russia has an increased capacity and an increased will to sail or fly with these resources," he said. "We do not think this in any way is directed against us as such, but is part of the overtly stated policy in Russia to continue to show their great power role," Mr Barth Eide said. "There has not been any violation of borders. These are open waters, and anyone is free to sail or fly there."

"We see it as a general part of the picture of relations between Russia and the West," he said. "An improved economy in Russia makes them able to invest in the military again and the ability to carry out these manoeuvres."

The military muscle-flexing comes before Russia holds parliamentary elections which polls show President Vladimir Putin's party is set to win.

Richer from oil and gas, Putin's Russia has boosted defence spending on its armed forces, which were starved of funding after the fall of the Soviet Union in the 1990s.

Russia's renewed military prowess in the region, including forays into Finnish airspace and Moscow's claim to the North Pole, have over past months forced Nordic nations to rethink their traditionally accommodating diplomacy towards the Kremlin.