Act president Catherine Judd plans to announce her resignation in the next few weeks.
A ballot of members will be held for a replacement and the results announced at the party's annual conference in late March in Wellington, the Herald understands.
Catherine Judd was re-elected before last year's general election
for a two-year term.
It is thought she did not support leader Rodney Hide during the bitter three-way leadership contest that she and the Act board set up after Richard Prebble's resignation in 2004.
But since his election she has publicly backed him and decided to stay on until after the 2005 election for the sake of party unity.
She became president in 2001, taking over the role from founder Sir Roger Douglas.
She could not be contacted yesterday.
Mr Hide said no announcement on Catherine Judd's job had been made but he did not believe any decision for her to go would be linked to his leadership.
Mr Hide did not endorse some of Catherine Judd's conclusions about the election, published in yesterday's Herald, from a confidential report to the party board in December.
He had a different take on her apparent criticism that the party had "no plan B" other than to win Epsom - which Mr Hide did.
He said Act had started off campaigning hard for the party vote nationally, with Epsom as the "second-string in our bow".
When the party realised it was not getting near the 5 per cent threshold "the plan was to go hard in Epsom and secure a public poll that would show that we could win the seat ... and that would open up the party vote for us [across New Zealand]".
The problem Act had was that people felt that giving their party vote to Act was "a wasted vote" because it appeared it wouldn't reach 5 per cent or win Epsom.
"So the Epsom vote was really to drive up our party vote [nationally]."
He said that unfortunately, the one Epsom poll in the campaign, by Colmar Brunton, had not been favourable to the party.
Mr Hide did not embrace Catherine Judd's view that he should establish himself as "the" Auckland MP and act more like a mayor.
"Being the mayor of Auckland hasn't been good for the last two mayors," he said.
