Megrahi, 57, was convicted of the Lockerbie bombing in 2001
The UK government will publish all correspondence with Scottish ministers on the Lockerbie bomber, Downing Street sources have said.
Information will be made public on Tuesday afternoon, when the Scottish Government also releases documents.
Scotland's justice secretary has meanwhile defended the medical advice he received before freeing terminally-ill Abdelbaset Ali al-Megrahi.
Kenny MacAskill insisted he sought a wide range of opinion.
It was understood the documents to be released by the UK government largely consist of letters from the Ministry of Justice, many of which have already been leaked, relating to the prisoner transfer agreement with Libya.
They are said to indicate there was no discussion about compassionate release of prisoners and reinforce the UK government's position that no deals were done over Megrahi's release.
Scottish ministers had already announced they would release documents on Tueday afternoon, ahead of a government-led debate on Wednesday.
Mr MacAskill earlier rejected claims by Scottish Labour health spokesman Dr Richard Simpson that he failed to consult appropriate specialists before releasing Megrahi on compassionate grounds.
The minister said: "In terms of medical reports, I received a clear report from the director of health and social care at the Scottish Prison Service.
"Whatever Dr Simpson may suggest, this wasn't done on the whim and fancy by the director of health and social care.
"It was done on the clear information and evidence - not simply his own professional expertise, but following the advice and information available to him from consultants who'd been dealing with Mr al-Megrahi during the course of his illness.
Kenny MacAskill said political or economic factors played no part in his decision
"There were numerous prostate cancer specialists, very many consultants."
It said it was "rather demeaning" for opposition MSPs to be "seeking to undermine the information provided by such a highly qualified medical professional".
However, Dr Simpson, who specialised in prostate disease research, later reiterated his criticism, claiming there was no medical consensus about the Libyan's prognosis.
"The justice secretary chose to disregard the advice of four specialists and release Megrahi on the opinion of one doctor, who we know was not a specialist," he said.
"At the very least, Kenny MacAskill should have sought a second opinion confirming the patient's prognosis from a specialist in palliative care.
"That he did not do so showed a disregard for due process and the significance of the decision."
Megrahi was freed on 20 August after serving eight years of a life sentence for the 1988 bombing.
A total of 270 people died when Pan Am flight 103 exploded over the town of Lockerbie in southern Scotland.
The Lockerbie bombing claimed the lives of 270 people
The decision to release Megrahi, who was greeted with a hero's welcome when he arrived back in Libya, has divided opinion.
It has been condemned by President Barack Obama, US Secretary of State Hillary Clinton and some of the families of American victims.
The director of the FBI, Robert Mueller, described the move as "making a mockery of justice" and one which gave "comfort to terrorists".
However, Mr MacAskill's decision received backing from Nelson Mandela, former First Minister Henry McLeish and the former lord advocate of Scotland, Lord Fraser of Carmyllie QC, who launched the case against Megrahi.
Meanwhile, the UK Justice Secretary Jack Straw described reports that the bomber was released over an oil deal as "wholly untrue".
He denied a "back door deal" was done to transfer Megrahi because of UK trade talks with the Libyan government.
Nicola Sturgeon, Scotland's deputy first minister, said it was no secret that the UK government had negotiated a prisoner transfer agreement with Libya.
She told the BBC's Today programme: "To be frank, I don't know what deals the UK government did or tried to do in the context of that agreement.
"It's certainly the case that al-Megrahi was not excluded from that agreement.
"What I do know, and can state categorically, as Kenny MacAskill and Alex Salmond have both done, is that these deals - if such deals existed - played no part whatsoever in the decision Kenny MacAskill took to release al-Megrahi on compassionate grounds."
She also insisted that Megrahi's decision to drop his appeal played no part in Mr MacAskill's decision.
"There was no pressure put on him by the Scottish Government and the Scottish Government had no influence in that decision," she said.
"In many respects the Scottish Government would have preferred the appeal to continue."
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