Labour's conference in Brighton is to get the chance to vote on calls for Tony Blair to set a date for British troops to pull out of Iraq.
Blair says he is restless to do more
Delegates forced the vote, which will take place on Thursday, when they chose the top five topical motions they wanted to debate in Brighton this week.
The news came hours after Mr Blair had said pulling troops out of Iraq now would be surrendering to terrorists.
The prime minister told the BBC he would not apologise for the Iraq war.
The other topical motions voted for debate were pensions, public services, workers' rights and manufacturing.
The Iraq vote will come during a wider session on "Britain in the World".
Thursday's motion will bring together a variety of debate proposals and there will now be behind the scenes persuasion to ensure the leadership wins.
BBC political editor Andrew Marr said Iraq threatened to dominate a great deal of the conference and there were fears about what hostage-takers in Iraq might do next.
Environment Secretary Margaret Beckett denied the vote was a blow to Mr Blair.
"It was always expected there would be discussion about Iraq at party conference," she told Sky News.
"But it is true that what we want to spend most of our time talking about this week is the future of Britain itself."
On Sunday evening, the brother of British hostage Ken Bigley told a conference fringe meeting he had new information that his brother was alive.
He urged Mr Blair to ask US President George W Bush to lift the "blockade" on releasing women prisoners in Iraq.
The prime minister spoke again to the Bigley family in Liverpool on Sunday, Downing Street said, but no more details have been given.
Earlier, Mr Blair told the BBC's Breakfast with Frost everything possible was being done to help Mr Bigley but he did not want to raise "false hopes".
Quizzed on reports he had considered resigning earlier this year, Mr Blair replied: "I'm not the wobbling sort."
Mr Blair admitted some of the intelligence used to justify the Iraq war had proved unreliable but defended the conflict.
"What some people want me to do is to say sorry for getting rid of Saddam and that I cannot say because I do not believe it," he said.
He went on: "When I hear people say because of the difficulties, we should pull our
troops out, my response is that would be to surrender to the terrorists."
As well as anti-war protests, thousands of hunting campaigners are set to march in Brighton on Tuesday to demonstrate against the planned hunting ban.
Asked why he had not voted on the issue in Parliament this month, Mr Blair said: "There was a compromise proposal last year and that was the one I backed."
The conference follows the government reshuffle that saw Alan Milburn appointed Labour's election co-ordinator.
Past election campaigns have been run by Chancellor Gordon Brown.
Mr Blair insisted Mr Brown would play the same role as he always had, but was not specific about what that would be.
Blair faces more hunting protests on Tuesday
Mr Blair said he was "restless to do more and do better".
He highlighted issues such as asylum, drugs, crime and organised crime and
reforming the education system.
The prime minister said his party had proposals on pensions, childcare and measures to help first-time buyers and tackle youth unemployment.
'Out of touch'
But his words failed to impress Liberal Democrat leader Charles Kennedy, who said: "The prime minister gives every
impression of being seriously out of touch with the genuine concerns over Iraq."
And Tory chairman Liam Fox derided confusion over what was running Labour's election campaign.
"With an ongoing war in Iraq, the countryside in chaos and public services failing to improve, the public are getting extremely fed up with the selfish bickering of Labour Party leaders," he said.
Thousands of campaigners joined a Trade Justice Movement march to demand fairer trade on Sunday.
Mr Brown later told delegates Britain would write off its share of debt owed by the world's poorest countries to the World Bank.