Two battles are emerging for Dáil seats in the by-elections in Dublin South West and Roscommon South Leitrim.
Counting continues and official results are not expected until later, but tallies suggest the favourites for the seats could be in trouble.
Final tallies in the Roscommon South Leitrim by-election show Fianna Fail's Ivan Connaughton is leading the way on 21.7% of the vote, followed by Independent candidate Michael Fitzmaurice on 18.6%.
Sinn Fein's Martin Kenny is next on 17.4%, while Maura Hopkins of Fine Gael is at 16.9%.
With just over 2,000 first preferences, Labour candidate John Kelly is way off the projected quota of 16,285.
Three boxes were missed in the tally, from Castlerea, Knockcroghery and Drumlea national school.
Paul Murphy credited the water charges debate with propelling his campaign, saying it "really struck a chord" with voters. "[It's] too early to call anything, but no question we're going to do extremely well."
"We're going to win, in a certain sense here, even if we don't win the seat - we'll be very well set up for a big battle on water charges [and] a seat in the general election."