Up to one in five people will face tougher identity checks before they will be allowed vote in the general election, under legislation to be approved by the Cabinet within the next fortnight.
The move is being taken because of persistent concern among the major political parties that some members of Sinn Féin may attempt to vote more than once.
Currently, polling station officers are required to challenge one in 20 people to prove their identities before issuing them with ballot papers.
The Minister for the Environment, Mr Dempsey, now believes this should rise to one in five, while fines for personation should also rise significantly. The changes will made in an emergency Electoral Amendment Act, which the Government has to pass before polling day to deal with a High Court ruling that candidates do not have to pay deposits.
Following a long-running battle, the Government finally gave up its battle late last year against Mr Thomas Redmond, of Coolree, Wexford, who had refused to pay deposits to run for the Dáil and the European Parliament.
The changes to the personation laws will not go as far as demanding that voters produce photo IDs. They will continue to be able to produce ESB or gas bills, among other items, as proof of identification.
Sinn Féin is expected to get three seats in the election: Kerry North, Dublin South West and Cavan/Monaghan. Its current 8 per cent standing in the opinion polls would see more seats fall to the party, if reflected on polling day.
The other political parties are expected to combine to challenge names on the electoral register to try to identify fraudulent voters, particularly in Dublin apartment blocks.
A new Register of Electors is prepared each year and comes into force on February 15th. To be eligible, voters must be over 18 and been "ordinarily resident" in the Republic on the September 1st before the election.
A large number of Sinn Féin supporters from Northern Ireland are believed to have used the addresses of friends in the Republic to register to vote in May, reliable sources told The Irish Times.
The other parties are expected to combine to ensure they have enough observers on election day to occupy key polling stations to prevent illegal voting.
Under existing law, party officials can insist that a polling station officer demand identification from a voter before letting them vote.