Fine Gael leader Leo Varadkar at Aras an Uachtarain in Dublin as he receives his seal of office as Taoiseach from President Michael D Higgins

New Taoiseach Leo Varadkar has vowed to lead a government of "the new European centre".

The son of an immigrant Indian doctor and Irish nurse was formally elected the country's youngest and first gay Taoiseach after securing 57 votes against 50 in the Dail.

Some 45 parliamentarians abstained in the vote.

Accepting his elevation to the most powerful office in the country, the 38-year-old leader of the minority ruling Fine Gael party rejected his characterisation as a right-winger.

"The government I lead will not be one of left or right," he said.

"While others in the house may be obsessed with the debates of the 1980s, I can assure you I am not and nor will my government.

"We will be focused on the solutions of the 21st century and the future.

"So the government I lead will be one of the new European centre, as we seek to build a republic of opportunity, and that is a republic in which every citizen gets a fair go and has the opportunity to succeed and in which every part of the country has a chance to share in our prosperity."

A qualified doctor who has held three Cabinet posts, Mr Varadkar only revealed he was gay months before Ireland, once regarded among Europe's most socially conservative states, became the first country in the world to back same-sex marriage in a referendum in May 2015.

His parents, Ashok and Miriam, and partner Matt Barrett, also a medic, were among the guests in the Dail's distinguished visitors' gallery for his election.

Paying tribute to his predecessor, Enda Kenny, who resigned on Tuesday, Mr Varadkar said: "I have no doubt, only for him, this country as we know it would not be here today.

"On a personal note, I would like to add, were it not for Enda Kenny I have no doubt I would not be standing here in this seat today."

The new Taoiseach, Ireland's 13th, was elected to the office exactly 10 years to the day since he first took his seat in parliament as a TD for Dublin West.

He has "grown and evolved" since then but was still motivated by a belief in the power of politics as the best way of solving problems and building a better future, he said.

One of his first official contacts as leader will be to British Prime Minister Theresa May to pass on the sympathies of the Irish people following the London tower block fire.

"The United Kingdom has been through some dreadful and terrible tragedies in the past few weeks, and to them, on behalf of this House, we offer our sympathies, solidarity and support," he said.

Mr Varadkar also vowed a "genuine willingness" to work together with all parties "on matters relating to Northern Ireland and matters outside the State".

"We all have responsibilities," he said.

"Our responsibility as a government is as co-guarantor of the (Good Friday) Agreement and of course the responsibility of all parties in Northern Ireland, after two elections, is to form an administration."

Mr Varadkar will meet the leaders of the Democratic Unionist Party and Sinn Fein in Dublin on Friday.

"Leadership should never be about just one person," he said.

"Leadership is not just about setting a course for the future, it is also about listening. In the months ahead, I will seek to do exactly that."

Mr Kenny said his successor would meet urgent challenges, including Brexit and Ireland's future in the European Union, head on.

"As the country's youngest holder of this office, he speaks for a new generation of Irish women and Irish men," he said.

"He represents a modern, diverse and inclusive Ireland and speaks for them like no other, an Ireland in which each person can fulfil their potential and live their dreams."

In a drawn out heave to replace Mr Kenny, Mr Varadkar secured the backing of a majority of the party's elected representatives earlier this month.

His rival in the race, 44-year-old father of three Simon Coveney, had the hearts and minds of most of the grassroots membership and has since been appointed deputy leader.

Mr Kenny announced last month he was stepping down after 15 years leading Fine Gael and six years as Taoiseach.

He had been under sustained pressure within his own ranks to allow a successor to be elected so the party is prepared for the next general election.

Questions already loom over how long Mr Varadkar can hold on to the office.

The administration is propped up by Fine Gael's ancient rivals Fianna Fail as part of a supply and confidence arrangement after an unprecedented schism in the electorate.

PA Media