IRELAND’S General Election is “wide open,” Leo Varadkar, the Taoiseach, has insisted, as the first voters cast their ballots with opinion polls putting Sinn Fein ahead.

Ballot boxes arrived under police guard in the country's Atlantic islands off the coast of counties Donegal, Galway and Clare on Friday morning with the opening of polling stations across the rest of the nation on Saturday.

On the Irish mainland, the leaders of the three biggest parties were making their final pitches of the campaign.

Mr Varadkar, who leads Fine Gael, was in Ennis, County Clare, where he expressed confidence his party would be returned on top despite recent opinion polls which have indicated a surge in support for his main opponents.

One snapshot for the Irish Times placed Sinn Fein on 25 points, Fianna Fail on 23, Fine Gael on 20, Independents and others also on 20, the Greens on eight and Labour on four.

But Sinn Fein’s ability to win seats is restricted given the party is only standing 42 candidates for the 159-member assembly; this compares to Fianna Fail with 84 and Fine Gael with 82.

Ireland's election uses a system of Proportional Representation.

Mr Varadkar dismissed predictions of a late surge for Fianna Fail and Sinn Fein as wrong, noting: “Any opinion polls that have been taken were taken before the big debate on Tuesday night which I did quite well in and before some of the controversies in relation to Sinn Fein became major news."

He continued: "It's a three-horse race; three parties all within shouting distance of each other. It's going to be down to the public. They are going to vote on Saturday, they'll decide which party is the largest party on Sunday and I believe that will be Fine Gael."

While the issues of health and housing have been prominent ones in the campaign so has Sinn Fein’s historic links to the IRA.

Micheal Martin, who leads Fianna Fail, was in Cork where he appealed to people who were undecided not to vote for Sinn Fein and said they had "not cleansed themselves of their bloody past".

He said he had promised voters he would not go into government with Sinn Fein and referred to the controversial campaign issue of the brutal murder of Paul Quinn by the IRA.

Calls have been made for Sinn Fein’s Conor Murphy, the Northern Ireland Finance Minister, to resign over his controversial claims made 13 years ago in the wake of Mr Quinn's murder when he branded the South Armagh man a criminal. Mr Murphy has since apologised for his remarks.

Meanwhile, canvassing in Dublin, Mary-Lou McDonald, the Sinn Fein President, pledged to use whatever mandate her party received wisely.

Urging people to go out and vote in "great numbers," she said: "The people were ahead of the curve in real terms in articulating the kind of profound change that they want, people were telling us: 'We want change and by the way you are it, so get ready and serve us well.'"