The more than 100 pages of documents suggested concerns were raised about the "reputational risks" in appointing Mandelson because of his friendship with Epstein but also over his previous resignations from government and his support for closer ties with China.
Starmer sacked Mandelson from what is considered the most prestigious posting in the United Kingdom's diplomatic service in September, when the depth of his friendship with the convicted sex offender started to become clear.
After ceding to pressure from the opposition Conservative Party last month to release the documents, the government published the first tranche but suggested more revealing exchanges could not yet be produced due to the police investigation.
A document labelled "Advice to the prime minister, checks conducted on 4 December, 2024", said: "After Epstein was first convicted of procuring an underage girl in 2008, their relationship continued across 2009-2011, beginning when Lord Mandelson was business minister and continuing after the end of the Labour government. Mandelson reportedly stayed in Epstein's house while he was in jail in June 2009."
In a summary of a fact-finding call between Starmer's general counsel and national security adviser Jonathan Powell in September, a document said Powell had found the appointment process "weirdly rushed".
Powell said he had concerns about Mandelson's "reputation" in conversations with Morgan McSweeney, then Starmer's chief of staff.
Another document dated December 11, 2024, said Starmer's director of communications was happy with Mandelson's responses to questions about his relationship with Epstein.
Despite Starmer's defence that Mandelson had lied to him over the extent of his relationship with Epstein, in parliament some opposition MPs said the documents showed the prime minister had known about their ties for some time.
"We're supposed to believe that the prime minister, who was once the chief prosecutor in this country, couldn't see through this nonsense," Conservative MP Alex Burghart said.
"It beggars belief."
Several MPs expressed shock over Mandelson's demands for severance pay.
He had asked for 547,201 pounds ($A1 million) in compensation after being fired but was given 75,000 pounds, in what the government described as a "reasonable settlement".
Further documents will be released at a later date, papers which the prime minister's team say will prove Mandelson lied to Starmer about the extent of his relationship with Epstein before his appointment as ambassador in December 2024.
Darren Jones, Starmer's chief secretary, told parliament that the government had learned lessons from the appointment and had taken steps "to address weaknesses in the system".
Mandelson, a government minister when Labour was previously in power more than 15 years ago, quit the House of Lords - the upper house of parliament - in February over his links to Epstein.
He was arrested last month on suspicion of misconduct in a public office and later released on bail.
Files released by the US Justice Department in January included emails suggesting Mandelson had leaked government documents to Epstein, and that the convicted offender had recorded payments to Mandelson or his then-partner, now husband.
Mandelson has said he does not recall having received payments.
He has not commented publicly on allegations he leaked documents and did not respond to messages seeking comment.
