The agreement comes as a Sunday Tribune/Millward Brown IMS opinion poll shows the coalition parties retaining an edge over the FG/ Labour alternative government.

McDowell and Tom Parlon met yesterday afternoon at the Leopardstown races; McDowell has also spoken to Liz O'Donnell, and Parlon was expected to meet with her yesterday evening.

McDowell now has complete control of the parliamentary party, with eight TDs and senators firmly in his camp.

An agreement will be struck in the next 24 hours that will see McDowell being elected leader unopposed, with Parlon taking over as party president.

Party sources were last night reluctant to completely rule out the possibility of Parlon forcing a contest.

However, the level of support for McDowell among TDs and senators makes the election of Parlon or O'Donnell extremely unlikely.

There are still reservations in senior levels within the PDs over McDowell becoming leader. "There is a view that Michael is not the person to be heading up the party. It's a serious concern, " one senior PD politician said.

But the desire to avoid division and present a united front . . . allied to McDowell's strong position . . . means that a contest is unlikely. It is understood that Liz O'Donnell has put the case for an agreed candidate.

Sources close to the Dublin South TD last night discounted speculation that she would find it difficult to serve under McDowell and might leave political life. "Liz will definitely contest the next election. Michael also needs Liz. There are not that many heavyweights in the party and Liz would have a different appeal to Michael, " one source said.

Mae Sexton has become the latest TD to signal her intention to support the justice minister. Sources close to the Longford deputy told the Sunday Tribune that they believed she would support McDowell if there was a leadership contest, and would like to see a significant role in the party for Tom Parlon.

After a traumatic week for the PDs, party members will be reasonably encouraged by today's opinion poll showing the party at 4%. Fianna Fail is unchanged from last November's Sunday Tribune/Millward Brown IMS poll at 37%.

Fine Gael is up two points to 26%; Labour is unchanged at 12%, the Greens are at 5%, while Sinn Fein is down by one point to 8%. The coalition has a three-point lead over the combined FG/Labour vote, although neither grouping would have sufficient seats to form a government based on these figures.

While Enda Kenny's personal popularity continues to rise, it is clear that Bertie Ahern remains a key electoral asset for Fianna Fail.

Asked to choose between Ahern and Kenny as to who would make a better taoiseach, 50% opted for Ahern, with 29% going for the Fine Gael leader.

The findings also suggest that Mary Harney picked the right time to stand down as PD leader. The nationwide poll of 1,097 voters was taken last Monday and Tuesday before Harney resigned. It showed a further drop of five points in her approval rating to 39%. Her dissatisfaction rating rose three points to 51%, by far the highest of all the party leaders and her worst performance in 11 separate IMS polls since 2002.

McDowell, in his capacity as the new PD leader, is expected to meet with Taoiseach Bertie Ahern on Tuesday. There remains unease on the FF backbenches about the implications of his election. Galway East TD Joe Callanan last night said Fianna Fail could continue in power irrespective of what the PDs decide to do. "There are enough Fianna Fail-minded Independents who could provide the numbers in order to provide a stable government, " he said.