A new report showed that the council is likely to be forced into using contingency funds if the missing funding is not found soon.
But it is now considered "extremely unlikely" that further contributions will be secured.
The total cost of the games is expected to be around £778m, with Birmingham City Council and other partners from around the region expected to provide around £184m.
A report to the city council’s resource overview and scrutiny committee has revealed that partner contributions to fund the games have not met expectations – with only £50m of the hoped for £75m accounted for so far.
It stated: “As has been previously reported to this committee the council’s initial expectation was that partner funding contributions towards the council’s £184.2m share of the cost of the games would be secured to the value of at least £75m including contributions from the West Midlands Combined Authority, regional local enterprise partnerships, local universities and the Midlands Engine.”
“Despite extensive engagement over a number of years at both political and senior officer levels to date it has only been possible to secure partner contributions amounting to £50m, with secured contributions from the West Midlands Combined Authority (£25m), Greater Birmingham & Solihull LEP (£20m) and Community Infrastructure Levy (£5m).
“It is anticipated that the entirety of this contribution will have been drawn down by March 31, 2022.
“Given the substantial impact on public finances as a result of the Covid-19 pandemic in particular, it is considered extremely unlikely that any further partner contributions will be secured.
“In recognition of the increasing likelihood of a £25 million shortfall in partner funding contributions, Cabinet agreed on July 27, 2021, that this amount should be set aside from the overall Corporate Capital Contingency - to mitigate the risk of this funding shortfall and ensure that the council’s commitments under the terms of the Host City Contract could continue to be met, and to ensure that the delivery of the capital investment required for the games was not undermined.”
Earlier this month, Birmingham Council leader Ian Ward said the city was on course to deliver the "best Commonwealth Games there’s ever been".
Councillor Ward said that the city was planning for a ‘full stadia’ despite the ongoing coronavirus pandemic, and confirmed that major construction projects remained on schedule.
The opening ceremony is due to take place on July 28 at the revamped Alexander Stadium off Walsall Road in Perry Barr.