MPs have called on the government to publish a list of companies using the furlough scheme.
It comes amid growing concern about what the Commons public accounts committee described as “opportunistic fraud” – where furloughed workers continue working while their bosses claim the grant.
It is thought this could be happening in between 7% and 34% of cases.
Under current plans the scale of losses will not be revealed until at least the end of next year but the committee said one should instead be released by the end of January.
Committee chair Meg Hillier said: “With the Treasury claiming it can’t give even a ballpark figure for the cost of COVID job support until the end of next year, public scrutiny of where taxpayers’ money is going is essential.”
The committee also says more should be done to help the 2.9 million people who were excluded from the furlough and income support scheme.
Ms Hillier said: “Many workers including freelancers and entrepreneurs have not had a penny and are really struggling as they continue to fall through the gaps.
“There is data that could be crunched to reach and help these individuals, many of whom will be unable to work at all under Tier 3 restrictions.”
In October it was revealed that the two schemes had cost more than £55bn but they have now been extended into next year – the furlough scheme is to run into April and the self-employed support into January.
The committee said: “HM Treasury and HMRC should investigate whether more data within and outside of the tax system could be used to determine eligibility for currently excluded groups and write to the committee within six weeks to explain their findings.”