The government is under pressure to release records relating to a multi-million pound PPE contract linked to Tory peer Baroness Mone.
In the House of Commons, Labour deputy leader Angela Rayner hit out at a "total failure of due diligence" as she asked about PPE Medpro winning a contract for personal protective equipment and "profits made possible through the company's personal connections to ministers".
"Last night, documents seen by The Guardian revealed that yet another case of taxpayers' money was wasted, a total failure of due diligence, and a conflict of interest at the heart of government procurement," she said.
"In May 2020 PPE Medpro was set up and given £203 million in government contracts after a referral from a Tory peer.
"It now appears that tens of millions of pounds of that money ended up in offshore accounts connected to the individuals involved, profits made possible through the company's personal connections to ministers and the Tories' VIP lane that was declared illegal by the High Court."
Ms Rayner said there "are rightly separate investigations into Baroness Mone's conduct, but the questions this case raises are far wider".
Michelle Mone, the Conservative peer who founded the lingerie brand Ultimo, is under investigation by the House of Lords Commissioner for standards.
Parliament's website says this is over "alleged involvement in procuring contracts for PPE Medpro leading to potential breaches…of the House of Lords code of conduct".
Ms Rayner said the government was refusing to publish correspondence relating to the award of the Medpro contract because they are still engaged in a mediation process.
In an urgent question to health minister Neil O'Brien she asked if that mediation process has reached any outcome "and what public funds have been recovered, if any?"
Mr O'Brien said it was "widely reported it had an underperforming contract" and laid out the process the government would pursue.
"The first step is to send a letter before action which outlines a claim for damages.
"And that's then followed by litigation in the event that a satisfactory agreement has not been reached.
"And to answer the right honourable lady's question directly, we haven't got to the point where a satisfactory agreement has been reached at this stage."
Downing Street would not be drawn on the allegations around Baroness Mone.
Ms Rayner said that while today's reports concern just one case "this government has written off £10 billion alone in PPE that was deemed unfit for use".
"Ministers appear to have learned no lessons and have no shame. As families struggle to make ends meet, taxpayers will spend £700,000 a day on the storage of inadequate PPE."
The government's use of high priority lanes to speed up the award process for PPE contracts during the pandemic have been branded "VIP Lanes" by critics, with Labour previously claiming there is a "cash for access" culture within the Tory party.
But being referred to the high-priority lane "was emphatically not a guarantee of a contract and indeed, nearly 90% of offers referred through the route were unsuccessful", the Downing Street spokesman said.
Baroness Mone has declined to comment on the latest allegations.