The Green Party candidate in the Dublin Bay South by-election has said she would like her supporters to give their second preference vote to Labour's Ivana Bacik.
Cllr Claire Byrne said she was making the comments in a personal capacity.
Senator Bacik said she would encourage her supporters to vote Labour first, then transfer to left and centre-left candidates.
When asked which parties she was referring to, she mentioned the Green Party and the Social Democrats.
Fianna Fáil’s candidate Cllr Deirdre Conroy, said it was up to each individual voter to decide who to give their second preference to. She said she would not tell her supporters how they should vote.
Sinn Féin’s candidate Lynn Boylan said she wanted her supporters to transfer to candidates on the left.
When asked whether she considered the Green Party to be a left-wing party, Ms Boylan said it depended on which member of the Green Party you were talking about.
Fine Gael’s candidate James Geoghegan said he would be asking people to support government candidates in the by-election.
"I’d ask people to give their number two to other government candidates in this by-election," he said.
The comments by the candidates were made in interviews recorded by RTÉ's This Week programme before the start of the campaign.
Last weekend Fine Gael’s director of elections, Minister Simon Harris encouraged government parties, including the Greens to form a pact to encourage their supporters to transfer to each other.
This proposal was rejected by Taoiseach Micheál Martin.
Mr Harris told RTÉ’s Morning Ireland on Monday: "I would imagine that the Taoiseach, when he thinks this matter through, would much rather have a TD in Dáil Éireann backing him, rather than a TD opposing everything he’s doing at this very important time."
