The Taoiseach had a telephone conversation with the new UK Prime Minister Gordon Brown this afternoon.
It is understood that the contact was initiated by Downing St, and that it took place within an hour of Mr Brown returning from Buckingham Palace
Mr Ahern has described Gordon Brown as a politician of exceptional experience and ability who would discharge the office of British Prime Minister with distinction.
He said that in this new era of British-Irish relations there was much to look forward to.
Of particular importance, he maintained, would be building on the foundation of peace in Northern Ireland.
Gordon Brown earlier succeeded Tony Blair as British Prime Minister. He met Queen Elizabeth at Buckingham Palace and accepted her invitation to form a government.
Speaking outside Downing Street, Mr Brown said he was absolutely sure that Britain could be the great global success story of this century.
The Prime Minister promised a new government with new priorities and said he would govern beyond narrow political interests.
Blair steps down
Tony Blair told his Sedgefield constituency Labour Party this evening that he was resigning as their MP.
He had formally applied for the so-called Stewardship of the Chiltern Hundreds, the traditional technical procedure for the resignation of an MPO, this afternoon having stood down as Prime Minister earlier today after 10 years in office.
He is to take on a new role as Special Envoy to the Middle East.
Describing the job as another colossal task, Mr Blair will act as an ambassador for the Middle-East Quartet: the US, the UN, the EU and Russia.
During his final Prime Minister's questions in the House of Commons, Mr Blair said the absolute priority in the Middle East is to seek a two-state solution to the Israeli-Palestinian conflict.
After his final session as Prime Minister in the House of Commons, he returned briefly to Downing Street to say farewell to staff before going to Buckingham Palace with his wife, Cherie, to hand in his seals of office to Queen Elizabeth.
Tributes
President Mary McAleese and Mr Ahern paid warm tribute to the outgoing leader.
President McAleese expressed her hope that Mr Blair would have the opportunity to pause and reflect on the significance of his achievements in Northern Ireland.
Sending her good wishes on behalf of the people of Ireland, Ms McAleese thanked the British Prime Minister for his 'extraordinary commitment' to the peace process during his time in office.
The Taoiseach also wished Mr Blair well in his new role as International Envoy to the Middle East.
Speaking on RTÉ Radio's Morning Ireland, Mr Ahern said Mr Blair confirmed to him that the role had been offered to him and he would be taking it up after he stepped down as Prime Minister.
He said he agreed with Mr Blair who believes that if there is direct engagement, similar to that applied to Northern Ireland, then the Middle East peace process could move forward.
On a personal level, the Taoiseach said he will miss Mr Blair; he said there was not a week in the past ten years when he did not speak to him at least twice.
The Taoiseach said he did not know Gordon Brown that well and that it would be a 'whole different relationship'.
The US Ambassador to Ireland, Tom Foley, has also paid tribute to Mr Blair, saying he had shown persistence and steadfastness in relation to the Northern peace process.
