David Cameron and Nick Clegg are set to publish a dossier detailing progress on 480 pledges made by the coalition Government, which will acknowledge that some targets have been missed.
Official sources said the document would be published on a Government website this week, and the Daily Telegraph reported that it could be as early as Wednesday.
The Deputy Prime Minister last month promised a "candid" audit of the Government's performance, but this did not feature in the Mid-Term Review published with great fanfare on Monday.
The new dossier is understood to be an annexe to the Review, which goes through every one of the 480 measures in the 2010 Coalition Agreement to update the public on what progress has been made.
The Telegraph reported that the document will confirm that the coalition has missed more than 70 pledges in areas ranging from pensions and road-building to criminal justice, and said its publication appeared to have been delayed amid fears that it would overshadow any favourable coverage of the Mid-Term Review.
Its existence was revealed when one of Mr Cameron's senior advisers, Patrick Rock, was photographed in Downing Street carrying a document discussing the advantages and disadvantages of releasing it, said the paper.
The restricted document reportedly warned that publishing the annexe alongside the Mid-Term Review on Monday could highlight "problematic areas" and lead to "unfavourable copy" identifying "broken pledges".
The Prime Minister's official spokesman said there had been a "long-standing intention" to publish the document but that it had been necessary to ensure it was fully accurate before releasing it.
He told reporters at a daily briefing: "I don't think it's news that the Government considers presentational aspects of its announcements. One of the very important ones, of course, being that when we publish things they are absolutely right.
It had now been "copper bottomed" with all Whitehall departments concerned, he said, and would be published later on Wednesday.