Ministers have defied calls to reveal details of their conversations with Rover directors in the run-up to the car giant's collapse.
Conservatives made a formal request, in a written House of Commons question, for details of discussions between the Department of Trade and Industry and Rover managers.
But Trade Minister Ian Pearson (Lab Dudley South) said it would be "inappropriate to release this information at this time".
It follows Tory claims, strongly denied by Labour MPs and Ministers, that the Government "bought forward" the date of Rover's collapse to prevent it becoming a damaging issue in May's General Election.
Conservative Trade spokesman Charles Hendry has asked the Government to publish transcripts of conversations and copies of correspondence between the DTI and senior managers at Rover in the crucial week beginning Monday April 4.
MG Rover's precarious financial situation became clear on Saturday April 2, when it was revealed the Government had offered it a #100 million bridging loan to help it stay afloat.
Two days later, it emerged talks with Chinese manufacturer SAIC, designed to save the Longbridge firm, had stalled.
On Wednesday that week, Tony Blair pledged to do "whatever we can" to save MG Rover, but by Thursday the firm's suppliers were refusing to deliver components, and late that evening Patricia Hewitt, the then Trade Secretary, revealed the firm had called in administrators.
Mr Hendry, who accused Ministers of being partly responsible for Rover's failure in a recent Commons debate, wants the DTI to reveal what was happening behind the scenes.
But Mr Pearson said: "It would be inappropriate to release this information at this time as it would breach commercial confidentiality and may prejudice the position of the administrators."
Last night Mr Hendry said: "If the DTI have nothing to hide about Patricia Hewitt's chaotic handling of the sad last days of MG Rover, why are they with-holding this crucial information?
"Once again the Government is showing its inherent reluctance to admit its own failings in this saga.
"These answers will make many people question whether the Government's hands are clean in this affair."
In his Commons reply, Mr Pearson also said the DTI was no longer in contact with SAIC and when asked if Ministers were still in discussions with Rover's directors replied: "There has been no ongoing contact between the Secretary of State and the former directors of Phoenix Venture Holdings since MG Rover's entry into administration."