More than a third of the further education sector's property has fallen into serious disrepair or will do so soon - and colleges fear they will not have the cash to make the necessary improvements.
According to Audit Scotland's report, Scotland's Colleges: current finances, future challenges, published last week, the Scottish government combined funding for colleges' and HE institutions' capital projects will reduce from pound;91 million in 2011-12 to pound;56.4 million by 2014-15 - a real- terms reduction of more than 45 per cent.
Around a third of the colleges' estate is in "as new" condition, says the report, but 37 per cent is "either at serious risk of breakdown, or requires major repair or replacement over the next three to five years".
Other sources of income to colleges dropped from pound;85.8 million in 2006-7 to pound;80.3 million in 2010-11, and were expected to reduce by a further pound;15.9 million in 2011-12, said Audit Scotland.
Faced with a cut in the government's core grant to the sector and an expectation that additional income, such as tuition fees, could also drop, colleges fear that maintaining and improving buildings and campuses will become increasingly difficult.
"The reductions in public sector capital funding available to colleges over the next three years mean that colleges are unlikely to be able to sustain the same level of new-build campuses as in recent years. Older buildings are likely to continue in use for longer and to require more costly maintenance," the report says.
John Henderson, chief executive of Scotland's Colleges, said: "Ensuring the estate is well maintained is also essential for it to last as intended. With energy prices rising, the costs of running estates also increase, squeezing colleges' resources further.
"The use and allocation of capital will need to be allocated in a highly strategic way, but it is difficult to see how all the repair and maintenance needs can be met while costs rise and the available budget falls in this way."
Since 2001-02, more than half of Scotland's colleges have either been newly built or had major refurbishments carried out on their campuses.
Audit Scotland cautioned that while these new buildings might require less maintenance in the short term, continuous investment was important so that "costly maintenance backlogs do not develop".
Institutions spent 5.2 per cent less on property maintenance in 2010-11, the first year of government cuts, than they did in 2009-10.
Capital funding for colleges has long been allocated via a formula based on student numbers, according to the Scottish Funding Council.
But education secretary Michael Russell's guidance letter to the SFC, published earlier this month, directed the body to move towards a more needs-based approach.
"During a challenging period for public finances, and capital in particular, the SFC must deliver maximum value for money from the funding available. Your capital investments must also be consistent with the strategic vision set out in Putting Learners at the Centre," said Mr Russell.
He expected the SFC's distribution of capital maintenance allocations in FE and HE to "balance the strategic and capital requirements of individual regions (or) institutions, with the need to maintain the value of previous investments".
Progress had been made with projects at Inverness, City of Glasgow and Kilmarnock colleges moving to procurement. To support these, the SFC's capital allocation included "funding to meet preparatory costs . which will be subject to ministerial approval".