The counting of votes in one of the tightest general elections in years began at 9am with exit polls showing Fianna Fáil replicating its 2002 performance and Fine Gael improving - but Labour and the PDs down.
With a higher-than-average turnout predicted, the RTÉ/Lansdowne Market Research exit poll showed the alternative coalition of Fine Gael and Labour on 36.2 per cent compared to 44.2 per cent for Fianna Fáil and the Progressive Democrats.
There was no breakthrough for the Greens nor Sinn Féin, while support independents fell significantly.
The poll's percentage figures were: FF - 41.6; FG - 26.3; Lab - 9.9; Ind 7.5; SF - 7.3; Greens 4.8; PD 2.6. The margin of error is 2.5 per cent.
The exit poll was accurate to within around 1 per cent in 2002, overestimating Fianna Fáil and underestimating Fine Gael.
Fianna Fáil's figure was up a fraction on the last election, while Fine Gael's figure was up by 3.8 per cent. Labour were down 1 per cent, the PDs down 0.5 per cent; Sinn Féin and Greens up by 1 per cent, and independents down 3 per cent.
Transfers will be crucial to the outcome of the poll, with the formal pact between Fine Gael and Labour to be tested to the full. On the basis of the first preference figures, none of the main propositions can form a government.
Labour has ruled out forming a coalition with Fianna Fáil. If it sticks to this commitment, the Greens allied to the governing coalition would be the most likely combination for forming a government.
Constituencies are expected to begin declaring the result of the counting of first preference votes by mid afternoon.
Although the Government parties had no formal pact, Fianna Fáil urged its supporters to transfer to the Progressive Democrats.
Fine Gael and Labour put an alternative alliance to the people from the outset with the Greens saying it wanted to see Fianna Fáil removed from office but refusing to sign up to an alliance.
Sinn Féin could have the power to support a government composed of either the existing coalition or the alternative alliance - possibly without the Greens - but all parties have ruled out allowing Sinn Féin a role.
There were 466 candidates standing for election in 43 constituencies. It is expected that 62.5 per cent turnout in 2002 will be well exceeded, assisted by the better weather this time around.
However, there were signs of voter apathy in inner city areas, while turnout in middle-class areas was particularly higher in better-off suburbs, and turnout in the commuter areas around Dublin is expected to be high.
County constituencies in Cork looked like delivering higher turnouts than the city, while turnout in counties Limerick, Kerry, Mayo, Waterford and Louth appeared high.