The taoiseach made the commitment yesterday after a week of confusion over how he would respond to Sinn Féin support in the Dáil following the general election.

However, in comments made to this newspaper ten days ago, before the controversy began, Tánaiste Michael McDowell said that although he accepted what the taoiseach had said about not going into coalition with Sinn Féin, "I don't accept that if they hold the balance of power that they won't decide who will be taoiseach, because that would be an undemocratic position".

Noting that the vote of every TD in the Dáil was equal when it came to electing a taoiseach, the tánaiste added: "If you have two rival candidates for taoiseach and their [Sinn Féin's] votes will determine which of these people gets office, they will exercise those votes and they will determine who becomes taoiseach".

McDowell insisted that his concerns about Sinn Féin's "Marxist world view" were legitimate. "I'm not just imaging this. They are allied with the Communist Parties in the European Parliament. Their newspaper [An Phoblacht] is full of articles about imitating the Cuban revolution. . . They're stuck in a time warp which is frightening. They are fundamentally hostile to the European Union, to liberal economics, to international investment, to Ireland being part of a globalised economy. All these things are anathema to them.

So if they held the balance of power and had a significant influence over policy in the Republic, it would be back to the future, " he said.

McDowell said this scenario would be "a disaster for Irish politics" as Sinn Féin remains " a party with a Marxist world view and an economic policy that is deeply at odds with Ireland's economic prosperity".

The tánaiste made the comments to this newspaper before last Sunday's highly-publicised remarks by the taoiseach on the subject. The taoiseach told RT�? radio that, while Fianna Fáil would not do any deals with Sinn Féin, it would not be reasonable for any party to say it would not take support offered from others if no deal were struck.

Ahern's comments led to accusations from Fine Gael that the taoiseach had abandoned his 2005 declaration that he would go into opposition rather than rely on Sinn Féin. However the taoiseach clarified his remarks yesterday. "I have consistently said that I will not form a government that is dependent on Sinn Féin votes, " he said.