Prime Minister Enda Kenny's outgoing coalition failed to win a majority in Irish elections, final results showed on Thursday, heralding tough talks to form a new government that could last for weeks.
Kenny's Fine Gael party won 50 out of 158 parliamentary seats, followed by traditional rival Fianna Fail with 44 seats, raising the possibility of an unprecedented coalition between the two.
Sinn Fein, the former political wing of the IRA in Northern Ireland which campaigned against budget cuts, won 23 seats and the Anti-Austerity Alliance-People Before Profit group won six seats.
Fine Gael and Fianna Fail, both centrist parties, trace their origins back to opposing sides in Ireland's civil war in the 1920s and long-standing allegiances will hamper any coalition talks.
An 80-seat majority in the parliament, or Dail, is required to govern and analysts have warned that another possible scenario is a minority government led by Fine Gael or Fianna Fail supported by smaller parties which could prove shaky at best.
The other possibility would be new elections.
The outgoing coalition campaigned on a platform of maintaining a recovery that has seen Ireland become the fastest-growing country in the European Union, but which many feel has yet to improve things for ordinary people squeezed by years of austerity cuts.
The swing to anti-establishment and anti-austerity parties echoed recent elections in other eurozone countries like Spain and Portugal which also led to political deadlock.
Weeks of uncertainty could lie ahead and the first test of whether a government can be formed will be March 10, when the newly-elected deputies are to meet in parliament and try to appoint a prime minister.
Established parties 'under threat'
Former prime minister Bertie Ahern has predicted there is "not a chance in hell" of a deal before Easter, at the end of March.
"It's not going to be easy and it's going to be long," Ahern told RTE radio earlier.
"It's a new game, there's no obvious combination that can work this out."
Exit polls which came out after Friday's election had already indicated that no party had won a majority.
Kenny himself conceded defeat on Saturday, telling RTE television, "Clearly the government of Fine Gael and Labour are not going to be returned to office.
"Obviously one has to wait now until all the counts are in right across the country to see what the options that must be considered are," he said.
Analysts have drawn parallels to Spain, where talks to form a government are still ongoing after a vote in December, and Portugal, where October elections resulted in an unstable minority Socialist government.
"There is a common pattern to many of these, which is that the established party systems are under threat," said Professor David Farrell, political scientist at University College Dublin.
"There's no doubt that one immediate cause is the ongoing experience of austerity and its impact on the wider citizenry."
Farrell called the result in Ireland a "wake-up call for the established parties".
"There's a decline in voter turnout that might suggest that our electorates are becoming turned off of politics, but in all sorts of other ways we can see our citizens being more turned on," Farrell said.
"They protest more, they express themselves through social media, they get involved in international charities or worry about the world economy," he added.
"All of this speaks to a citizenry that is more engaged and the job for the elected politicians is to try to find ways of engaging with that in a new way."
Voter turnout in the Irish vote was 65.1 percent, lower than the 70 percent in the previous 2011 election which came after a banking crisis and bailout that precipitated the fall of a Fianna Fail government.