IF Brian Cowen does stand down in the coming days, there will be a straight contest between finance minister Brian Lenihan and foreign affairs minister Micheál Martin, TDs say.

It will be the first serious contest for the Fianna Fáil leadership since the historic 1979 battle between Charles Haughey and George Colley, which split the party for years afterwards.

And there are already predictions that the contest between Lenihan and Martin will be rough. "It will be bitter and it could get dirty," one senior party figure said this weekend. "It's the last chance for the Lenihans [to secure the leadership] and Micheál is also well able to mix it."

Although tourism minister Mary Hanafin's name is routinely mentioned when future leaders are being considered, the view in the parliamentary party is that Hanafin would not be able to muster sufficient support.

She has been one of the party's best performers in recent months and is highly respected but sources say she antagonised TDs during her tenure as education minister throughout which they claim she was difficult to deal with. "There is an argument that as Julia Gillard has done really well in Australia and Angela Merkel is hugely popular in Germany that Hanafin would bring a new dimension to politics. That said, she is not popular within the party," one TD said.

Hanafin is very close to Martin and would be appointed as his deputy leader if he takes over from Cowen, giving the party a nicely balanced male-female, Dublin-Cork ticket.

There was speculation this weekend that if the Martin camp does decide to move against Brian Cowen, it would be Hanafin, rather than Martin, who would move a confidence motion. There was no indication from Hanafin or Martin that this is a likely scenario.

Lenihan would have been comfortably elected leader if the contest had happened a number of months ago. But he has been damaged by the fall-out from the EU-IMF intervention and many TDs believe he has been overtaken by Martin in the succession stakes. But the contest is a lot tighter than recent indications and nobody can be sure how it will turn out.

Martin also has his detractors who point out he was the minister who set up the HSE and was minister for enterprise and employment at a time when the budget at Fás was getting out of control.

Both men are seen as excellent communicators. Martin would be able to draw considerable support from his Munster base, which is said to be "utterly loyal to him". He may also have the edge among cabinet ministers, given he has served with them longer than Lenihan. However, cabinet support was of little use to George Colley 31 years ago.

Lenihan is perceived to have strong support in Dublin and among midlands and border deputies. He may also have the edge in the west. Counties such as Meath and Kildare are said to be split pretty evenly between the two men.

Lenihan's relatively safe seat in Dublin West could play to his advantage, with some TDs claiming that Martin's seat in Cork South-Central is not as secure. Hanafin is even more vulnerable in Dun Laoghaire. "Some of the people who are being named as leadership contenders are not sure of holding onto their seats. Where would we be if we got a new leader before the election that did not hold his or her seat?" one TD asked.

And not everybody in the party is enamoured by the likely choice on offer. A member of the party's so-called Ógra generation said this weekend: "None of us at our level in the party feel particularly close to Micheál Martin, Mary Hanafin or Brian Lenihan. They are all aloof in their own ways. We only really see them in the Dáil chamber and apart from that you only get access if you can make your way past their battery of advisors. The exception to that is if you are a member of the 'bar lobby' as they have their own mechanisms for getting in contact with the leadership.

"At the moment, the Ógra generation does not have the support to put forward a leadership candidate, but if we get to a point after the election where the leadership comes up we will certainly be looking into putting somebody forward."

But matters might come to a head before that point. Martin has been sounding out deputies for over a week now while TDs say that Lenihan has been talking to people for months and making it clear he's available if required.