A post-Games review from MPs has raised doubts that £2bn worth of London 2012 funding from the National Lottery will be repaid.
The donation ensured the Lottery would be reimbursed from future returns from developments at the Olympic Park, which was developed using the public funds it boosted.
The Public Accounts Committee (PAC) said it was "not clear" that the Lottery's interest is being "adequately promoted and protected" by the London Legacy Development Corporation (LLDC), which is in charge of securing the economic future of the Park.
The MPs suggest the Government should develop "a mechanism" to ensure the LLDC's decisions are transparent and prioritise the interests of the Lottery.
They said current projections suggest the first repayment to the Lottery will not be until the mid-2020s.
More top news
Donald Trump has wasted no time making his mark on international matters as well as domestic. So how will his presidency affect the world?
Another cold, frosty and foggy night for many. Northern and western areas will see thickening cloud, patchy rain and milder temperatures.
Temperatures have already plunged to -12C in some parts of the UK this winter - but Thursday could be the coldest day yet.