Green Party leader Trevor Sargent has warned Fine Gael and Labour that his party would "walk away" from any potential coalition unless they agreed to a radical change in policy.
"I don't want any position in a government that will just be rearranging the deckchairs on the Titanic," said Mr Sargent in an interview in the latest edition of Magill magazine.
"I think we're certainly serious about having our policies implemented. But any presumption that we would settle for a role in government that would not deliver on the serious policy areas we've been outlining for years is quite wrong. There wouldn't be any point in us being in government in that case."
He noted that Fine Gael leader Enda Kenny had yet to discuss with him a potential coalition, adding: "Our policies are quite different from what we hear from all other parties at the moment.
"If the other parties don't appreciate the need for serious change in this country then I'm quite prepared to walk away, let them think it over and come back to me."
Asked what the Greens had in common with Fine Gael, Mr Sargent replied: "I regard Fine Gael as a broad church, and I'm sure there are people within it who see the need for radical change.
"I haven't had an opportunity yet to find out if Enda Kenny is one of them. But I'm an eternal optimist. And I like Enda; he is someone who listens. He doesn't have the airs and graces associated with some people in politics."
