Blair reiterated allegations that ousted Iraqi President Saddam Hussein had posed a “threat” to the Middle East and world at the start of his Labour party’s annual conference on Sunday.
But the prime minister urged people to wait for an interim report later this week from a US investigation into Iraq’s alleged possession of weapons of mass destruction.
However, Blair said he did not regret the war.
“I don’t apologise for Iraq. I am proud of what we have done,” he said in a televised interview on Sunday.
As close political ally, Labour Chairman Ian McCartney predicted Blair would stand in another two elections. The prime minister came out fighting at the conference, billed as his toughest since he became party leader in 1994.
Opening the conference, McCartney urged members to put their differences aside or risk losing office, after a new opinion poll revealed deep rifts in the party.
Labour is facing its worst poll ratings since Blair took over as leader and led the party out of 18 years in political exile to two successive landslide election victories.
Blair vowed no retreat from reforms to British education and health sectors which have angered many in his centre-left party.
Blair's trust ratings have plunged after the war launched against Iraq in March.
The failure to find weapons of mass destruction - the main justification for the war – and the suicide of an expert on Iraq's arms and the inquiry into his death have all damaged him.
“I don’t apologise for Iraq. I am proud of what we have done"
British Prime Minister
Scientist David Kelly killed himself after he was named as the probable source of a BBC report that said London had over-exaggerated a pre-war dossier on the alleged threat posed by Iraq.
In a poll published in a British newspaper, 41% of Labour members said they wanted Blair to resign before the next election.
McCartney warned the conference that bickering could cost Labour the government.
“We have to draw a line under our differences and face the next milestone and the next milestone after that,” he said.
Blair dismissed remarks by former UN chief weapons inspector Hans Blix that Hussein had destroyed weapons of mass destruction in 1991.
“Why on earth was he obstructing the (UN) inspectors all the way through the 1990s?” said Blair.
Asked if he had contemplated quitting in the face of plunging popularity, he said: “No, I didn’t.”
Blair said his party was going through a difficult patch but would not retreat from planned education and healthcare reforms.