Sinn Fein will be the third largest party in the Republic after Friday’s general election.
Hours after ballot boxes opened for counting on Saturday, it became clear that the incumbent Fine Gael/Labour coalition have no chance of being returned to power on their own.
Under Gerry Adams, who topped the poll in Louth, the party looks set to continue its march south of the border with an expected increase in its vote and its presence in the Dail parliament by around 50%.
Micheal Martin, the opposition leader in the last Dail parliament, insisted the focus was not entirely on bringing an end to 90-odd years of civil war politics by taking power with Fine Gael.
“We have made it clear we do not want to go into government with Fine Gael or with Sinn Fein,” he said.
“The idea that it is just down to two parties, I think, is ignoring the reality of how people voted.”
Sinn Fein president Gerry Adams said he had “divided thoughts” on a potential Fine Gael-Fianna Fail coalition.
“They are natural partners, they are Siamese twins who have been divided for some time - they should get into bed together,” he said. “That’s my positive attitude.
“My negative attitude to it is, this would be a most conservative regime if they do come together.
“It would be another broken election promise as they were both elected not to go into government with each other.”
Mr Adams hailed his own party’s showing as he arrived in the Louth count centre in Dundalk.
He embraced his running mate Imelda Munster, who is set to be elected with him - becoming the first woman TD elected in Louth.
Mr Adams said if a “progressive” government did not take power on this occasion, it was “only a matter of time” before it happened in the future.
“One thing is for certain, this change is going to continue,” he said.
Mr Adams said he had told party faithful to keep on “election footing” in case there was another poll.
According to surveys of people leaving polling stations by pollsters Ipsos MRBI for the Irish Times and by Behaviour and Attitudes for state broadcaster RTE, Sinn Fein, Independents, smaller parties and newcomers are all likely to make significant gains.
The first exit poll showed Fine Gael on 26.1% of first preference votes; Labour on 7.8%; Fianna Fail on 22.9%; Sinn Fein on 14.9%; Anti Austerity Alliance/People Before Profit on 3.6%; Greens on 3.5%; Social Democrats on 2.8%; Renua on 2.6%; and others on 16.1%.
RTE’s showed Fine Gael on 24.8% of first preference votes; Labour on 7.1%; Fianna Fail on 21.1%; Sinn Fein on 16%; Anti Austerity Alliance/People Before Profit on 4.7%; Greens on 3.6%; Social Democrats on 3.7%; Renua on 2.4%; Independents on 11%; and the formal Independent Alliance on 3%.
However, the figures come with a health warning, given Ireland’s unusual single transferable vote system.
The outgoing junior government partner Labour fears an electoral bloodbath as Tanaiste, or deputy prime minister, and party leader Joan Burton gears up for a dogfight to retain her own seat.