Tony Blair will make a statement to MPs on the outcome of the Butler Inquiry into intelligence about Iraq's weapons of mass destruction capability.
There have been accusations that the inquiry's remit is too limited
Commons Leader Peter Hain told MPs the prime minister would make his statement on the day of the report's publication - scheduled to be Wednesday 14 July.
Mr Blair called the inquiry after no WMD stockpiles were found in Iraq.
The timing of the publication means the report will come out on the eve of two key parliamentary by-elections.
They will take place in the normally safe Labour seats of Birmingham Hodge Hill and Leicester South.
The report's publication also comes just two days after the government's comprehensive spending review, which sets out the public cash plans for 2005-2008.
The Liberal Democrats always refused to take part in the Butler inquiry, saying it was too narrow, and the Tories later pulled out too.
BBC political editor Andrew Marr said it would be a "frenetic" week of politics and it was also possible it could end with a cabinet reshuffle.
The Hutton inquiry cleared the government of "sexing up" intelligence in its dossier on Iraq's alleged weapons.
The new inquiry, headed by former Cabinet Secretary Lord Butler, is examining the actual intelligence which led to the decision to go to war - something not covered by the Hutton inquiry, whose remit was the circumstances surrounding the death of Dr David Kelly.
Lord Butler said he would focus on "structures, systems and processes" rather
than the actions of individuals. The Tories said that was too restrictive when they withdrew their cooperation.
But Tory MP Michael Mates, who continued on the inquiry in a personal capacity, has suggested the report might trouble the government.
He told the Times newspaper that Downing Street had brought forward the by-elections from 22 July because it did not want the report "wallowing around" being "unpicked by the media" for a week before the votes.
Asked if he was suggesting the report would be bad news for the government, Mr Mates reportedly replied: "The government may well think that."
Ministers have not seen yet seen the findings but Mr Mates said they had been told of the "body of fact". That could give an indication of possible criticisms.
Tony Blair's official spokesman said the Butler team had announced the publication date.
The spokesman said: "They
let us know the date that they wanted the report to be published on. We are
relaxed about when the date is."