Projects at 330 colleges have already been agreed
The government has appointed a trouble-shooter to investigate delays in the re-building of sixth form and further education colleges in England.
Sir Andrew Foster is to lead an independent review of the £5bn renovation programme.
Decisions on 20 colleges have been postponed until March by the funding body, the Learning and Skills Council.
The LSC insists there is no freeze on the programme but says some colleges are having trouble raising funds.
Opposition politicians have demanded an explanation from the government, saying the confusion illustrates the reality of Prime Minister Gordon Brown's pledge to bring forward capital works to help counter the economic recession.
The Department for Innovation, Universities and Skills said the pace of demand for funding by colleges overall had increased, with the scale of the projects - and the government funding required - becoming increasingly ambitious.
"In addition there are early signs that the ability of colleges to raise their own funds for to help pay for proposed projects is being affected by the downturn," a spokesman said.
"Many proposed schemes rely on either the sale of land or other assets and on the ability of colleges to gain financial support from the banks. This may have an effect on the private funding available for schemes."
So the LSC had been examining the position of colleges intending to submit bids before making further funding decisions.
"As a result of this the consideration of a small number of applications that were due for decision - both in principle and in detail - has been deferred from December to March."
Skills Secretary John Denham - who is said to be furious at the turn of events - said the college renovation programme had been a huge success, funding nearly 700 projects at 330 colleges, with more than 250 under way.
But he added: "It's right that we look at how the programme is working and Sir Andrew Foster is well placed to do that."
Sir Andrew - a former chief executive of the Audit Commission - has previously led an inquiry into the whole future of the further education system in England.
Shadow innovation, universities and skills secretary David Willetts said: "This is the reality of Gordon Brown's so-called 'fiscal stimulus'.
"Far from capital projects being brought forward they are actually being delayed.
"Not only are students of FE colleges missing out on the rebuilding they have been promised, but more building firms could go to the wall as they are hit by the government's three-month delay to capital spending.
"John Denham must urgently come to Parliament to explain what on earth is going so badly wrong in his department. MPs from all parties have been contacted by concerned FE colleges."