Hollywood actor Sean Penn has weighed into the Falklands dispute amid growing tension between Britain and Argentina.

Just last week the UK was forced to dismiss claims it was "militarising" the situation in the South Atlantic by deploying nuclear weapons nearby.

Penn met Argentine president Cristina Kirchner in Buenos Aires and urged Britain to join United Nations-sponsored talks over what he called "the Malvinas Islands of Argentina".

"It's necessary that these diplomatic talks happen between the United Kingdom and Argentina," he said. "I think that the world today is not going to tolerate any kind of ludicrous and archaic commitment to colonialist ideology."

The Oscar-winner, 51, made the comments following months of escalating rhetoric between the two nations.

Most recently, Argentina has said it had intelligence that a Vanguard submarine had been sent to the area and demanded to know whether it was carrying warheads.

"Thus far the UK refuses to say whether it is true or not," foreign minister Hector Timerman said. "Are there nuclear weapons or are there not? The information Argentina has is that there are these nuclear weapons."

The accusation, made through a translator, came as Mr Timerman urged the UN to intervene in the long-running row over the islands.

But Britain's ambassador to the UN, Sir Mark Lyall Grant branded the idea that the UK was "militarising" the situation "manifestly absurd".

In recent months, Prime Minister David Cameron and President Kirchner have traded barbs prompting UN secretary-general Ban Ki-moon to issue a statement expressing "concern about the increasingly strong exchanges".