The Iraq Inquiry report must be published before the "incomprehensible and unacceptable" expected date of June or July because people have already "probably" died as a result of the ongoing delays, MPs have been told.
Conservative David Davis wants the Chilcot report published as soon as national security vetting is complete - expected to be in early May after the Government promised the process would take a fortnight or less.
Cabinet Office Minister John Penrose said the report into the Iraq War should be handed next week to officials for security checks, which will be completed within two weeks as promised by David Cameron.
But Mr Penrose stressed that inquiry chairman Sir John Chilcot will still need to prepare the "very large" report for publication and will announce a firmer release date after vetting.
The minister told a backbench debate on the inquiry: "I should make clear that at that stage, even when the national security checking process is complete, the report will still be in Sir John Chilcot's hands and will not be released to the Government until everything is ready.
"The inquiry has said that it will complete the remaining work as swiftly as possible, and as Sir John Chilcot indicated in his letter to the Prime Minister last October, that he expects publication in June or July this year."
Responding to speculation that the report may be delayed until after the EU referendum on June 23, Mr Penrose that there is nothing in the "purdah" rules for the poll to stop the inquiry's publication beforehand.
But Mr Davis said waiting until June or July to publish the report would be difficult to understand for many, including the families of the British war dead.
And he said recent decisions about intervention in Libya, Syria and Iraq were made without proper knowledge of the controversial 2003 choice to go to war.
As a result bad decisions have been made which have probably cost lives, the former foreign minister added.
Mr Davis told the Commons: "There are lessons to be learned from the Iraq War about our foreign policy, about our political decisions to go to war and about our military operations.
"The longer we leave it the less useful these lessons will be and the more likely it is that we will make the same mistakes.
"A decision such as those that were made in Libya, Syria and Iraq are made without the knowledge or facts, mistakes are made, and sometimes people die as a result.
"It's not hyperbole to say delay to the Iraq Inquiry could cost lives because bad decisions could be made - I would go further, I'd say it probably did cost lives because bad decisions were made."
He later added: "I want to say through the minister to Sir John Chilcot that June/July is incomprehensible and unacceptable."
Several other MPs called for the publication of the report as soon as possible.
The SNP's Angus MacNeil (Na h-Eileanan an Iar) said: "The UK risks becoming an international laughing stock by this infinite and eternal delay that's tied with this report."
Former British Army officer Bob Stewart, Tory MP for Beckenham, said: "I think we could sum up what the military families feel by the fact that the longer this takes, the more jiggery-pokery they think is going on with actually the results of the inquiry.
"If we keep going on and on like this there will be total loss of faith in what it produces."
Labour's Graham Allen (Nottingham North) said the publication would be good for the party: "The publication will be part of what is necessary to purge our own party of the fault line that occurred around the time of the Iraq War and continues to this day."
The SNP's Martin Docherty-Hughes (West Dunbartonshire) said: "The longer we wait, the more unstable our position becomes and this has led successive British governments to continue with this same failed philosophy without ever learning from the mistakes or looking at a different set of responses to the situation in which we now find ourselves."
Labour's Paul Flynn (Newport West) said: "It is absolutely crucial we understand that mindset that drove us into war - and that mindset is one that we heard recently in other debates here, with going into Libya, or into Syria, and is this myth, that affects English MPs rather than Scottish or Welsh or Irish MPs, and it's the idea that the UK, our country, must punch above its weight militarily."
Liberal Democrat Tom Brake (Carshalton and Wallington) said: "Since the Iraq war of course we have had the first involvement in Libya where, if the Chilcot Inquiry had been published, that I'm sure would have helped the decisions taken there."