Ireland's three main parties are tied neck-and-neck following Saturday's general election according to an exit poll, leaving the question of who will control the next government hanging in the balance.

Prime Minister Leo Varadkar's incumbent Fine Gael party, their centre-right rivals Fianna Fail and left-wingers Sinn Fein all received 22 percent of first preference votes, according to the Ipsos MRBI poll issued as the polls closed at 2200 GMT.

The survey of around 5,000 voters leaving the polls -- which has an estimated margin of error of 1.3 percent -- put Fine Gael on 22.4 percent, Sinn Fein on 22.3 percent and Fianna Fail on 22.2 percent.

Composition of the Irish parliament, ahead of Saturday's general election
Composition of the Irish parliament, ahead of Saturday's general election AFP / Vincent LEFAI

However, Ireland uses a single transferable vote system to elect multiple deputies from each of the 39 constituencies, making it hard to extrapolate a likely seat forecast from the exit poll figures for first preference votes.

That means the outline of the next parliament will only start to become clear during the count, which gets under way at 0900 GMT on Sunday.

"We've never seen a general election result like it. Basically a statistical tie between what are now the three big parties," said Pat Leahy, political editor of The Irish Times newspaper.

He told RTE television that forming a government could prove "a very difficult exercise" unless parties compromised on their pre-election stances ruling out particular coalition arrangements.

Voters will go to the polls for an election that has become a historic three-way fight for power
Voters will go to the polls for an election that has become a historic three-way fight for power AFPTV / Mathilde BELLENGER

Both Fine Gael and Fianna Fail, which have traditionally held a duopoly on power, pledged they would not form a coalition with Sinn Fein, the former political wing of the now-defunct Irish Republican Army paramilitary group.

Meanwhile Fianna Fail said they would not back Fine Gael in a "grand coalition".

But analysts told AFP this was likely to be pre-election "posturing".

Prime Minister and leader of the Fine Gael party Leo Varadkar says the election is wide open with polls giving Sinn Fein -- the former political wing of the IRA paramilitary group -- a slight lead over centre-right Fianna Fail
Prime Minister and leader of the Fine Gael party Leo Varadkar says the election is wide open with polls giving Sinn Fein -- the former political wing of the IRA paramilitary group -- a slight lead over centre-right Fianna Fail AFP / Ben STANSALL

Varadkar was hoping to secure a new term on the back of his Brexit strategy.

He plumped for an early election after successfully helping to broker a deal cushioning Britain's EU exit on January 31 by avoiding a hard border with Northern Ireland, part of the United Kingdom.

However, the campaign was dominated by domestic issues -- notably healthcare and housing -- and opinion polls showed Fine Gael losing ground.

As the ruling party seeks to retain control of government in Dublin, voters seem less preoccupied by the fallout from Brexit than issues such as healthcare, housing and homelessness
As the ruling party seeks to retain control of government in Dublin, voters seem less preoccupied by the fallout from Brexit than issues such as healthcare, housing and homelessness AFP / Ben STANSALL

The exit poll paints a more optimistic picture for Varadkar, but since no party seems set to secure a majority it is likely negotiations will begin as votes are counted.

In office since June 2017, Varadkar, 41, is Ireland's first mixed-race and openly gay premier who has come to represent a more socially progressive Ireland after years of dominance by the Roman Catholic Church.

Varadkar, whose party has been in power since 2011, cast his vote on the outskirts of Dublin, seeming in a relaxed mood as he chatted with officials and posed for selfies with voters.

The campaign was dominated by domestic issues -- notably healthcare and housing
The campaign was dominated by domestic issues -- notably healthcare and housing AFP / Ben STANSALL

Polls opened at 0700 GMT, although a small number of islands off the west coast voted on Friday to allow for rough seas potentially disrupting the transport of ballots by boat.

In the capital, a stream of voters made their way to polling stations on Saturday.

Liam Allen, 27, said housing was a "big concern" for him.

"I still live at home with my parents and for the foreseeable future I won't be able to afford a home," he told AFP.

Nurse Terry Sanor said: "I'm hoping that the health service will improve, and the waiting list, and the pay for the nurses and the housing."

Either Fine Gael or Fianna Fail have traditionally held the reins of power.

"I'm hopeful there will be change. In this country, for far too long it's been dominated by two parties," said 60-year-old James Comiskey.

Alexander Faw, 22, said: "I'm looking for a more left government of Ireland."

Some 3.3 million people were eligible to vote to elect 159 members of the Dail, the lower chamber of parliament in Dublin.

Fianna Fail leader Micheal Martin, 59, voted with his family in his Cork city constituency.

"We are very confident. We had a good campaign," he told reporters outside the polling station.

"Housing and health and the impact of the cost of living on people have been the dominant issues of this campaign."

Sinn Fein leader Mary Lou McDonald voted in central Dublin.

"They want a change in representation and they want a change in government."