The Taoiseach, Mr Ahern, has sent a message of congratulations to East Timor in recognition of its independence.
The Pacific island, ravished by Indonesia’s brutal occupation, declared its hard-fought independence shortly after midnight (3 p.m. Irish time) today in front of tens of thousands of revellers, proudly taking its place as the first new nation of the millennium.
Standing on a makeshift stage in a field on the outskirts of the capital Dili, UN Secretary General Mr Kofi Annan handed over the reins of power to loud cheering from the crowd.
Former guerrilla leader Mr Xanana Gusmao was due to be sworn as president minutes later.
In his message, Mr Ahern said: "On May 20th the world will witness the establishment of a free and independent East. Mr Gusmao’s long struggle has been rewarded with this achievement which is warmly welcomed by the people of Ireland.
"I would like to affirm to you that the support and the interest of Ireland will continue as you move into the next phase of nation building."
The UN has administered East Timor since late 1999, when the half-island nation voted overwhelmingly to break from 24 years of iron Indonesian rule that left a quarter of the population dead from fighting, famine or disease.
Impoverished East Timor, home to 740,000 people, was a Portuguese colony for some 350 years before Indonesia invaded in 1975.