"We must finalise and adopt a federal law on the southern border of Russia's Arctic zone," Mr Medvedev told a meeting of the Security Council, in remarks carried by Interfax news agency.
"This is our responsibility, and simply our direct duty, to our descendents," he said. "We must surely, and for the long-term future, secure Russia's interests in the Arctic."
Global warming has stepped up the fight for the disputed Arctic, believed to be laden with vast reserves of oil and gas. Russia has pitted itself against Canada, Denmark, Norway and the United States to fight for a greater part of the region, arguing that most of it is Russian territory since an underwater ridge links Siberia to the North Pole's seabed.
Last August, a Russian mini-submarine carrying politicians and scientists plunged to the depths of the Arctic and claimed to plant a Russian flag to mark Moscow's stake in the territory.
Footage of the alleged planting was widely broadcast on Russian television – but later turned out to be images taken from the Hollywood blockbuster Titanic.
Under international law, each of the five countries that lay claim to the Arctic own a 320-kilometre zone that extends north from their shores. That arrangement is up for UN review in May next year.
Vladimir Putin, now Russia's prime minister, has said global warming is good for Russia – melting its vast icy territories to reveal previously inaccessible oil and gas reserves.
With oil production declining – and Russia's oil-fuelled power rising – it is keen to grab ever more.
"This region has strategic significant for us. Its development is directly tied to solving the long-term tasks of the state and its competitiveness on global markets," Medvedev said.
Russia's leaders have not held back on stoking issues sure to rile the West in recent days, despite a drastic drop in its markets, fuelled by the global credit crisis and compounded by loss of investor confidence in Russia after its war with Georgia.
Medvedev's statements on the heated Arctic issue came one day after Putin said that Russia's defence spending would rise 27 per cent next year to nearly $100 billion (£30 million).
