Britain accused Argentina of colonialism in its claim to the Falkland Islands on Wednesday, as the 30th anniversary of their conflict over the British-ruled territory approaches.

A day after Britain's National Security Council discussed the Falklands' defences, Prime Minister David Cameron told parliament Britain was committed to protecting the South Atlantic islands and added that people there should be allowed to decide their own nationality.

Cameron said he was determined that the islands' defences were in order and that islanders' wishes were paramount. We support the Falkland islanders' right to self-determination, he said.

What the Argentinians have been saying recently I would argue is actually far more like colonialism because these people want to remain British and the Argentinians want them to do something else.

Last June Argentine President Cristina Fernandez described Britain a crass colonial power in decline for refusing to hold talks over the islands, known as Las Malvinas in Spanish.

Britain's argument of self-determination was a display of mediocrity bordering on stupidity, she said.

London has controlled the islands, about 300 miles off the Argentine coast, since 1833. Its two-month war with Argentina in 1982 resulted in the deaths of 255 British and about 650 Argentine soldiers.

The British government says it will only agree to sovereignty talks if the territory's 3,000 residents ask it to, and that the islanders want to remain British.

Tensions have risen in recent years over offshore oil exploration, and have gained steam ahead of the April anniversary of the conflict as well as the planned tour of duty on the islands by Britain's Prince William, an RAF helicopter pilot, later this year.

In December, the South American trading bloc Mercosur agreed that vessels sailing under a Falklands Islands flag would be banned from docking at any of its ports as an act of solidarity with Argentina.

Foreign Secretary William Hague began a visit to Brazil, part of Mercosur, on Wednesday as part of British efforts to strengthen political and economic ties with Latin America.

(Additional reporting by Adrian Croft; Editing by Ben Harding)