Left-wing nationalist party Sinn Fein said on Thursday it had formally requested talks with center-right rival Fianna Fail to discuss options for forming a new Irish government following an inconclusive election last weekend.
The request puts pressure on Fianna Fail leader Micheal Martin, whose party has 38 seats in the 160-seat parliament, to clarify his position on a possible tie-up with Sinn Fein, which has 37 seats.
Sinn Fein, Fianna Fail and the center-right Fine Gael Party of Prime Minister Leo Varadkar secured just under a quarter of seats in parliament each, meaning it will be hard to form a government unless at least two of the three cooperate.
Surveys showed that voters rejected the traditional parties over the key campaign issues of healthcare and the high cost and low availability of housing, won over by Sinn Fein's high-spending promises and a pledge to freeze residential rents.
During the election campaign, Martin ruled out doing a deal with Sinn Fein, the former political wing of the Irish Republican Army (IRA), but in the immediate aftermath of the vote, he refused to completely exclude the possibility.
"Micheal Martin has said 'I am a democrat, I listen to the people and I respect the decision of the people', so he knows that the people have voted for change," Sinn Fein leader Mary Lou McDonald said in a statement to announce that the formal request had been made.
"There is an obligation on all of us to act urgently," she added.
Fine Gael and Fianna Fail have long shunned Sinn Fein, citing policy differences and the party's historic links to the IRA, which fought British rule in Northern Ireland for decades in a conflict in which some 3,600 people were killed before a 1998 peace deal.
Both parties are also opposed to Sinn Fein's high-spending promises, its pledge to scrap property tax and plans to hike income taxes on high earners they say would discourage foreign multinationals that employ one-in-10 Irish workers.
There are open divisions among Fianna Fail lawmakers over talking to Sinn Fein. Two members of parliament, one a senior member of Martin's front bench, strongly ruled it out on Thursday ahead of the party's first meeting since the election.
The Irish Times newspaper said Martin was expected to rule out such a coalition.
The two lawmakers, Niall Collins and newly elected Cathal Crowe, suggested that Fianna Fail could instead lead a minority government similar to the previous administration Varadkar led via a co-operation deal with then main opposition Fianna Fail.
"There are a number of minority type administrations that could be put together with each of the three parties involved and essentially underscoring a confidence and supply arrangement," Collins told national broadcaster RTE.