Defence Secretary Geoff Hoon has appealed for the Labour Party to end its divisions over the Iraq war and unite around a shared vision for the country's future.
Hoon has been suffering the glare of bad publicity
In a highly charged debate at Labour's annual conference in Bournemouth, Foreign Secretary Jack Straw also robustly defended the war - which he described as the government's toughest foreign affairs decision.
But other delegates accused Prime Minister Tony Blair of "lying" about the case for war as the continuing splits on the conflict were laid bare.
The Iraq conflict was discussed as part of a wider debate which saw delegates approve Labour's foreign policy on a show of hands.
Both sides of the argument are being put just hours after the prime minister spoke of his continued determination to prevent more "repressive states" obtaining weapons of mass destruction.
The Iraq debate comes after party leaders were defeated in a vote on foundation hospitals, one of the government's key NHS reforms.
In his contribution to the debate, Mr Hoon said: "Whatever differences exist on the question of military intervention. Now is the time to agreed on a shared vision of the future of Iraq."
Mr Hoon has come under repeated media attack during the Hutton inquiry into the death of government scientist Dr David Kelly but he was heard politely by Labour delegates.
Like the defence secretary, Mr Straw said the post-war situation in Iraq was unsatisfactory but argued progress was being made in getting schools, universities and hospitals running again.
"Slowly, if too slowly, the reconstruction work is starting to create a future for the people of Iraq they have dreamed of for so long," he said.
"We have helped to liberate the people of Iraq from Saddam, but I accept that liberating them from his brutal legacy will be longer and harder."
Earlier, Halifax MP Alice Mahon said the country had been "seriously misled" in the run-up to a war which had made the world a much more dangerous place.
"The truth about this is that our prime minister promised President Bush that he would support his war for oil," she said.
RMT delegate Mick Hogg complained that his union's motion specifically challenging the case for the war had been thrown out by conference organisers.
"It is a tragedy and a shame that a government of Labour - the party of peace and justice - has taken us to war for reasons that are simply untrue," he said.
Other speakers backed the war, pointing to the serious dangers which would have come from failing to act as Iraq flouted United Nations resolutions.
The most emotive speech came from Ann Clwyd, Mr Blair's human rights envoy for Iraq.
The left-winger won a standing ovation as she argued that Mr Blair had done the right and "moral" thing in destroying the terror of Saddam Hussein.
'No blind eye'
With tears in her eyes and her voice almost breaking, Ms Clwyd said: "In June this year I stood on the edge of Saddam's killing fields, I saw the skeletons of men, women and children being dug up."
She continued: "I do not believe, and neither do you, we should turn a blind eye to such atrocities."
Labour officials insisted that there was always the chance of a debate and a vote on Iraq.
But union leaders said a deal was only cobbled together on Tuesday night in a meeting of the conference arrangements committee.
Earlier, Afghan President Hamid Karzai gave a reminder of one of Mr Blair's other international interventions as he told how his country had improved since the fall of the Taleban.
In a rare interview for BBC Radio 4's Today programme, Mr Blair said the big security threats facing the world were completely different from those seen during the Cold War.
He said: "It is the prospect of chaos and disorder from a combination of terrorism and these deeply repressive states, states for example like North Korea, spending literally billions of dollars on nuclear weapons capability whilst their people starve...
"I believe if we do not deal with this threat, if it strikes again like 11 September or even worse, I promise you that the consequences for our own safety and security, the stability of our economy will be absolutely enormous."
He argued that if no stand had been taken over Iraq, there would now be no dialogue with North Korea and Iran would not be cooperating with United Nations nuclear inspections.