Britain said on Monday it was creating one of the world's biggest marine reserves around a cluster of South Atlantic islands claimed by Argentina, a move that may fuel tensions already rising before the 30th anniversary of the Falklands war.

The declaration of a reserve covering more than 1 million sq km (386,000 sq miles) of ocean around the remote British territories of South Georgia and the South Sandwich Islands is designed to protect the fragile environment in an area teeming with penguins, seals and seabirds.

But Britain's move, which puts severe restrictions on fishing in the area, could anger Buenos Aires which claims sovereignty over South Georgia and the South Sandwich Islands as well as the Falkland Islands which lie about 1,000 km (620 miles) to the west of them.

In 1982, Britain sent a force to reclaim the Falkland Islands and South Georgia after Argentine forces occupied them. About 650 Argentine and 255 British troops died in the 10-week conflict.

Tensions between Britain and Argentina have risen again this year as the 30th anniversary of the war approaches and as British companies drill for oil off the Falklands, called Las Malvinas in Spanish.

Argentina complained to the United Nations this month over what it called Britain's militarisation of the South Atlantic and both countries have traded accusations of colonialism over their claim on the Falklands.

On Monday, provincial authorities in Argentina stopped two British-linked cruise ships from docking in Tierra del Fuego, raising the temperature further.

The creation of the marine reserve was announced by Nigel Haywood, governor of the Falklands and the Queen's representative in South Georgia and the South Sandwich Islands, who signed the measure into law.

The declaration of a marine protected area around South Georgia and South Sandwich Islands clearly demonstrates the UK's effective environmental stewardship of this unique and remote part of the world, British Foreign Office Minister Henry Bellingham said in an accompanying statement.

TALKS RULED OUT

Foreign Ministry officials in Buenos Aires could not immediately be reached for comment on Monday, a public holiday in Argentina. The embassy in London was also closed.

London has refused to open talks on Falklands' sovereignty with Buenos Aires unless the 3,000 islanders want them. Britain denies militarising the region but says it would robustly defend the islands if necessary.

In December, South American trading bloc Mercosur banned fishing boats flying the Falkland Islands flag from many South American ports, a step analysts say was part of Argentina's campaign to undermine Britain's hold on the islands.

Argentine President Cristina Fernandez has also criticised a decision to post Prince William, second-in-line to the British throne, to the Falklands this month for a six-week tour of duty as a Royal Air Force search-and-rescue pilot.

South Georgia and the South Sandwich Islands are uninhabited except for scientists and a few government officials.

Fishing will be banned entirely in an area around the coast of each island, totalling more than 20,000 sq km or about the size of Wales, and restricted elsewhere.

Environmental group Greenpeace said the marine life in the waters around South Georgia was of global significance and clearly demands comprehensive protection but it said it wanted to see international agreement to create a network of marine reserves throughout the Southern Ocean.

Greenpeace believes that the creation of marine reserves should be a step towards peace, not conflict, Ruth Davis, chief policy adviser at Greenpeace UK said in a statement.

(Additional reporting by Helen Popper and Hugh Bronstein in Buenos Aires; Editing by Alison Williams)