LONDON - BRITAIN sparked a diplomatic spat with Argentina on Thursday by announcing a new constitution that updates its powers over the Falkland Islands - the object of a brief war between the countries in 1982.

The new constitution, which will enter force on January 1 to replace a version agreed in 1985, boosts local democracy while 'retaining sufficient powers for the UK (United Kingdom) government to protect UK interests', the British Foreign Office announced.

'What it does not do is change the UK government's overall commitment to the Islands as an Overseas Territory,' said junior foreign minister Gillian Merron, after the constitution was agreed on Wednesday.

'Nor does it change the right to self-determination, fundamental to our relationship with all of our Overseas Territories,' she added in a statement.

But Argentina, which 26 years ago challenged Britain militarily over control of the islands, known in Spanish as the Malvinas, sharply criticised the new constitution, saying it had lodged a formal complaint with London.

'It constitutes a flagrant violation of the mandate accorded us by the United Nations', Argentine Foreign Minister Jorge Taina said at a press conference.

'The Argentine government will denounce this violation of Argentine sovereignty and international law before the international community', Mr Taino added, saying Britain was trying to perpetuate 'an anachronistic colonial situation.'

The Falklands conflict erupted when Argentine forces invaded the islands, on April 2, 1982, prompting then-British prime minister Margaret Thatcher to deploy naval forces to retake the territory.

After a 74-day conflict, in which 649 Argentines and 255 Britons were killed, Buenos Aires surrendered on June 14. But Argentina still lays claim to the islands.

'The world has moved on since the previous Falkland Islands' constitution came into operation in 1985, and the Falklands have developed considerably both economically and socially', said the British minister.

'The new constitution reflects this,' she added, noting that the document creates a new Public Accounts Committee and a Complaints Commissioner among other changes.

Mr Mike Summers, spokesperson for the Falkland Islands' government, also welcomed the new document.

'The new constitution more accurately describes the relationship between the Falklands and the United Kingdom, and formally establishes the degree of internal self-government', he said, cited by the Foreign Office statement.

'We have been pleased with the cooperative nature of our negotiations, reflecting a maturing partnership and a continuing commitment to security, social and economic development'.

'The right of the people of the Falkland Islands to determine their political future has been freely exercised through the democratic process', he added.

The new Falklands constitution was formally approved by Queen Elizabeth II on Wednesday after negotiations on the basis of a parliamentary report published in April 2007.

The report took account among other things of the framework of arrangements between Britain and all of its 14 Overseas Territories, which include Gibraltar, Bermuda, the Cayman Islands and the British Antarctic Territory.

In April, Argentina's President Cristina Kirchner reiterated Buenos Aires' claim to the islands.

'The sovereign claim to the Malvinas Islands is inalienable,' she said in a speech marking the 26th anniversary of Argentina's ill-fated invasion of the islands, located 480 kilometres off shore.

Argentina's embassy in London did not immediately respond to a request for comment on the new constitution.

But an Argentine constitutional scholar in Buenos Aires, Daniel Sabsay, told AFP the new constitution was merely 'more of the same'. 'It's a new affirmation of the way Great Britain brazenly ignores the sovereignty Argentina has, which the country has claimed in international forums and which appears in the revised 1994 (Argentine) constitution,' he said. -- AFP