SIPTU General Secretary Jack O'Connor has said the new Labour Party leader needs to insist there is no more unnecessary austerity as long as the public finances remain on their present trajectory.
The union leader said he was not sure if Fine Gael would go along with that and if it means the end of the Government "then so be it."
He was speaking after his own speech at a Labour leadership husting.
The husting was held in Dublin for party members who are also members of unions.
Mr O'Connor said he will support the candidate who commits to ensuring there will be no more austerity or cuts to working people.
Or to those depending on public services if the public finances continue in the current trajectory.