"At a time when many small states are embroiled in violent conflicts, Tuvalu has remained stable and serene," he said.

The UN, Mr Annan said, was "a forum where all nations are heard, regardless of their size", adding that he was "confident that the voice of Tuvalu will prove to be an eloquent one in our family".

He added that he expected Tuvalu, which last week also became a full member of the Commonwealth, would benefit from the UN's education and development programmes.

Known as the Ellice Islands when it was ruled by Britain for much of the last century, Tuvalu gained independence in 1978.

It is the fourth smallest country in the world in terms of area - behind the Vatican City, Monaco and Nauru. In terms of the population it is the second smallest, with only the Vatican City having fewer people.

Two years ago an international panel of human rights observers cited Tuvalu as the only nation in the world above reproach for human rights violations.

Big earners

Since achieving independence much of Tuvalu's foreign earnings have come from the sale of it postage stamps.

However, under a recent deal signed with the California-based company Idealab the country could be set to make millions from the internet - in particular from its unique .tv domain suffix.

Convinced that television companies around the world would want to buy their own Tuvaluan web address, Idealab bought exclusive rights to register .tv web domains though the start-up company dotTV.

In return Tuvalu, which retains a 20% share in dotTV and a seat on the board, is guaranteed to receive $4m a year for the next decade.

The government says the money will be used to improve the welfare and education of islanders and has already built two primary schools with money from the deal.