Turnout in the Tipperary south by-election is now estimated at around 35 per cent, with voting reported to be brisk.
Rural areas are showing stronger turnout than urban areas, but polling stations remain open until 10 o'clock tonight.
This is the first time in the history of the State that polling has taken place on a Saturday.
Four candidates are vying for the seat left vacant by the death of Fine Gael deputy Teresa Ahern last year.