Irish leader Leo Varadkar resigned tonight after suffering a crushing defeat in a parliamentary vote.

No clear successor emerged from political wrangling today designed to decide who will lead the country following a near three-way tie in a general election two weeks ago.

Varadkar lost a vote to remain taoiseach today, and told parliament he would resign as a result.

The Fine Gael party boss added he would stay on as caretaker leader after he tended his resignation to Irish President Michael Higgins.

He will be staying on as interim leader while the country's three main parties battle out deadlocked coalition talks after the inconclusive election.

Varadkar 'has this evening conveyed to the president his resignation from office,' the government said in a statement.

'In accordance with the constitution, the [prime minister] and the government will continue to carry on their duties until successors have been appointed.'

Taoiseach Leo Varadkar (right) waving as he left Aras An Uachtarain after tending his resignation to President Higgins (left) today

Leo Varadkar departing and shaking hand with President Higgins after tendering his resignation today

Sinn Fein leader Mary Lou McDonald arriving for the reconvening of the 33rd Dail following the recent Irish Election two weeks ago

The Irish Dail sat for the first time today, some 11 days after the outcome of the general election produced a different political landscape.

But parliamentarians failed to elect a taoiseach at its first sitting after the election on February 8.

None of the leaders of the four main political parties nominated for taoiseach emerged with a majority to secure the role.

Varadkar and Fine Gael leader Leo Varadkar, Fianna Fail leader Micheal Martin, Sinn Fein leader Mary Lou McDonald and Green Party leader Eamon Ryan were all nominated.

Mr Varadkar travelled to the Aras an Uachtarain, the office of the president, to officially resign.

He told the Dail before stepping down: 'The responsibility is on all of us to ensure we provide good government, and indeed good opposition.

'I think the onus is on those who have made enormous promises of change to the people during this election who are entrusted with that mandate to bring a programme of government for approval.

'If they cannot, they should say so and be upfront and honest about their failures and the empty promises they made.'

He said he will travel to Washington DC for the traditional St Patrick's Day events.

Taoiseach Leo Varadkar with other members of the Fine Gael party during the first sitting of the 33rd Dail in Dublin today

The Irish parliament siting today as votes were cast for nominations of the new taoiseach

Fianna Fail leader Micheal Martin (centre) arriving to speak to the media with other party members ahead of a new parliamentary session today

Earlier today Fianna Fail said it will start formal talks next week to try to form a government from the fractured parliament.

Left-wing nationalists Sinn Fein shocked the establishment by securing the most votes in the election but ran too few candidates to win more than 37 seats, finishing between Fianna Fail and Prime Minister Leo Varadkar's Fine Gael in the 160-seat house.

The centre right rivals refuse to govern with Sinn Fein but initially let the former political wing of the Irish Republican Army attempt to form a left wing-led government without them, knowing they are highly unlikely to succeed.

The 160 members of parliament gathered at Leinster House today where all their names were read into the record by the Clerk of the Irish parliament.

Sinn Fein leader Mary Lou McDonald received the most votes today backing her.

At 45 it was far short of the 80 needed to take office but it was a symbolic victory reflecting the surge the nationalist party enjoyed in the election.

Sinn Fein, which once served as the political wing of paramilitary the Irish Republican Army (IRA), became the second biggest party with 37 seats - breaking the historic duopoly of centre-right parties Fine Gael and Fianna Fail.

'The people who vote for us aren't going anywhere,' said McDonald.

'We have made a commitment to them to represent them well and to make our very best effort to deliver that government of change - and that is precisely what we intend to do.'

Newly re elected Ceann Comhairle Sean O Fearghail and Taoiseach Leo Varadkar in the Dail Chamber during the first sitting of the 33rd Dail in Dublin today

Sinn Fein leader Mary Lou McDonald (centre) being congratulated by supporters and fellow elected TDs as she arrived for the reconvening of parliament

McDonald outstripped the 36 votes backing Varadkar to continue as prime minister after his Fine Gael party slipped into third position in the election with 35 seats.

'The onus is on those who have made enormous promises of change to people during this election, who are entrusted with that mandate to bring a programme for government to the Dail for approval,' Varadkar said in parliament before departing to resign.

'If they cannot, they should say so and be upfront and honest about their failure, and the empty promises they made.'

Micheal Martin's Fianna Fail party won the most seats in the election at 38, but suffered significant losses on their 2016 wins.

He received the backing of 41 politicians in today's contest.

Sinn Fein has been historically associated with the IRA which fought British rule in Northern Ireland for decades until the late 1990s, when a peace agreement largely ended violence that left more than 3,000 dead on all sides.

It won the popular vote with 24.5 per cent of first preference ballots and picked up 14 seats by attracting voters with a campaign focusing on Ireland's housing shortage and health crisis.

But its flagship policy on Irish unity is likely to be a top issue if it gains power. It wants a referendum on uniting the two parts of the island within five years.

At least three parties will be needed to form a majority government in the Dail.

But with the three largest refusing to cooperate newly elected speaker Sean O Fearghail said the challenge of government formation remained 'substantial'.

Leo Varadkar leaving the president's office, Aras An Uachtarain, after tending his resignation

Fianna Fail leader Micheal Martin arriving at the reconvening of the Irish parliament today following the recent general Election

Independent TD Denis Naughten said there is 'public frustration' over accountability in public services.

Fianna Fail and Fine Gael have both ruled out working with Sinn Fein, in part because of their association to past violence.

Varadkar told state broadcaster RTE on Monday he was prepared to go into opposition.

Meanwhile Sinn Fein said on Wednesday it was 'intensifying' negotiations with smaller parties and independents seeking 'a government for change'.

Talks may take some time and may result in a new election in which Sinn Fein could emerge as a favourite.

After a 2016 vote it took 70 days for a minority coalition government to form under Fine Gael, which was supported in a confidence and supply agreement by Fianna Fail.

Mr Martin secured 41 votes in support, with 97 TDs voting against him. Mr Ryan received 12 votes in support and 115 votes in opposition.

Mr Martin accused Sinn Fein leader Mary Lou McDonald of using 'populist tropes' as she accused them of failing to speak to her in government formation talks.

The Healy Raes give a rousing rendition of the Rose of Tralee at their much anticipated pre Dáil concert. pic.twitter.com/bcEOQnd2Yx — Áine McMahon (@AineMcMahon) February 20, 2020

Irish Prime Minister Leo Varadkar speaking at a count centre near Dublin, during Ireland's general election on February 9. The resulted ended in a three-way deadlock

'Every party and deputy elected to this house has a right and a duty to represent the mandate they received. In order to deliver functioning government, compromises have to be made and this is something we have been attacked for.

'Demanding that others stay quiet as others abandon their core beliefs in order to grab power is not something we agree with.

'Whether or not you agree with Fianna Fail, we fought this election based on a clear set of principles and policies and that includes legitimate behaviour in a democratic republic.'

Mr Martin says he rejects Sinn Fein's manifesto promises of increasing taxes on businesses and too many incompatibilities exist between the two parties.

Ms McDonald told the Dail: 'Today for the first time a nominee other than Fianna Fail or Fine Gael has garnered the greatest number of votes. Perhaps that makes us winners again.

'I still we still live rent free in Micheal Martin's narrow and bitter mind.

'Change means a secure roof over people's heads, not having their adult children living in the box rooms.

'Change means you know you have enough to get by. Changes means dealing with the climate emergency. Change means the old order must pass.

'A vote for Sinn Fein was for a different government that would have the courage and energy to actually do things differently.'