Members of Ireland's 158-seater legislature, Dail Eireann, are elected on the basis of a universal, direct and secret ballot. According to its proportional representation with a single transferable vote system, candidates are elected or eliminated based on voters' ballot preferences.
If a candidate receives more than the determined quota to be elected on any count, the surplus votes are transferred to the remaining candidates in proportion to the next available preferences indicated by voters.
The ruling Fine Gael-Labour coalition is being challenged by six opposition parties and independent candidates. Opinion polls suggest no party will secure an outright majority to form a single-party government.
The latest polls indicate that Fine Gael will gain up to 30 seats, followed by its main rival Fianna Fail – the party that was in power at the time of the economic crash that brought the country to the edge of bankruptcy – with up to 23 seats, and the republican party Sinn Fein with up to 19 mandates.
Voting closes at 22:00 GMT, and counting is scheduled to begin early on Saturday and continue over the weekend.