Progressive Democrats leader Mary Harney has rejected supporters' calls to stay in the post, insisting that she wants to stand down by Christmas, or early in the New Year.
The determination of the Minister for Health and Children to quit now ensures that the party will have to hold a leadership election, under new rules that are finally to be agreed by the party's general council next month.
Former Dún Laoghaire TD Senator Fiona O'Malley is the favourite to take over, though it is not still not clear if Galway Senator Ciaran Cannon, who unsuccessfully contested Galway East in the general election, will run.
Ms Harney said: "I don't want to rush anybody's fences but it is not my intention to lead the party in the medium term and certainly some time around Christmas I look forward to handing over to my successor as leader.
"I'm only doing this purely as an interim arrangement after the general election in order to facilitate the party's deliberations in this matter. My focus is on the Department of Health and Children, on continuing to pursue the health reform agenda.
"That's my sole focus over the next number of years," said Ms Harney. "I will obviously assist the party in any way I can and the new leader of the party but hopefully the party can have a mechanism in place to decide on who that person should be between now perhaps and the end of January/February kind of timeframe."
Asked if she is planning to quit politics at the end of this Dáil, she said: "Well, I haven't made up my mind yet in relation to the next election. When I came into Leinster House 30 years ago into the Senate I said then I wouldn't be still there when I was 40. That was my plan then and clearly my plan changed somewhat and I'm not somebody that plans that far ahead. The next election is five years away and I'm certainly not going to make any decisions now that I might regret."
Under the new leadership election rules, PD TDs and Senators would have a smaller voice in future election contests, with councillors and ordinary members having a greater say.