Moves have already begun to oust Taoiseach Brian Cowen if last week's disastrous poll ratings are replicated in the elections on 5 June, Fianna Fáil sources revealed this weekend.

A disgruntled rump in the parliamentary party is talking openly, but off the record, about the possibility of Dermot Ahern or Micheál Martin as successors to Cowen, although it is believed that neither man will do anything to undermine the Taoiseach.

One informed source told the Sunday Tribune: "Quite frankly, I think he's finished''. "There looks to be no way back. They're circling him," was the verdict of a different government TD.

A third Fianna Fáil TD admitted he was "not happy with Cowen's leadership. His communication is brutal". The TD said he and a lot of like-minded TDs would not "rock the boat", but added: "There are a number of guys and I can't imagine them not doing something if we have a really bad result come the 5 June."

The three weeks in the run-up to the 5 June poll will be crucial, TDs who spoke to the Sunday Tribune conceded. "We are in the s**t. We need to see a bit of life to him [Cowen],'' said one.

There are mixed views in Fianna Fáil as to whether Cowen could be replaced as leader and Taoiseach without a general election. But one Fianna Fáil TD said: "It is an option. It's in the mix. There will be a lot of soul searching over the next few weeks."

There is a view that Cowen's reaction to a bad result in the elections will be crucial.

"Nobody wants a general election. Not even the maddest of our backbenchers. TDs will stand back and see what heads are put on a plate if any. Then you may see a concerted heave. If the Taoiseach waits until September to do a [cabinet] reshuffle, that could be fatal," one said.

However, other sources said that following this weekend's Irish Times tns/mrbi poll, the Cowen camp is confident the election result will not be as bad as expected and that the Taoiseach will be secure.

They point to yesterday's result showing Fianna Fáil with a strong chance of holding its four Euro seats.

"If we win four, that's the end of the talk, regardless of what happens in the locals," one source said.

Cowen backers say the serious discontent is confined to a small group of backbenchers who will "make noise but nothing more than that".

They are convinced the party will be in the mid-to-late twenties, percentage wise, in the local elections, rather than the 20% shown in Friday's poll, which would limit the damage. This performance, allied to a likely 'Yes' vote in the Lisbon Referendum in the autumn, will "steady the ship", they say.

There is also nervousness within government about a number of difficult decisions it will have to make in the coming months.

Sources highlighted the potential difficulty of getting the legislation for the National Assets Management Agency (Nama) through the Dáil. No matter how many times Nama's merits are explained, the huge potential exposure to the state makes it difficult to sell, one senior government figure admitted, adding: "It's going to be shaky, very shaky."

There is also concern within government as to how the Greens will react to a probable poor performance in the local elections. "That could be more of a problem [than the backbenchers]," said one source. However, Green TD Paul Gogarty said yesterday: "if the Greens get annihilated in the locals, we are not going to go out looking for a general election... Turkeys should not vote for Christmas so we should use our influence in government over Fianna Fáil rather than going out looking for another beating."