The report by DTZ Pieda Consulting, issued on Wednesday, warns of "significant pockets of low participation" across the country, in advanced and non-advanced FE courses. The consultants believe this means that "the system could grow substantially" - on top of an 18 per cent increase in numbers over the past five years.
Yet college principals have been pointing out that they are constrained by a standstill in funding from the Scottish Executive over the next two years.
The estimate of the extra money required is based on what would be required to bring areas of low participation up to the national average. The funding council now plans to open talks with groups of neighbouring colleges to see what steps can be taken to turn things around.
Laurence Howells, the council's director of strategy, says this might include joint curriculum planning, estates planning, sharing administration resources and greater collaboration over marketing.
Mr Howells made it clear the council would increasingly link funding to the area exercises. This had already started in Glasgow, for instance, where money was given to FE libraries on condition they pooled their resources.
The report shows dramatic variations in participation, calculated on rates per thousand of the working population. Glasgow colleges have the best record at 31 per cent above the national average, while Argyll and Bute and Lanarkshire are 25 per cent and 24 per cent below.
High participation is being achieved in the north-east, Fife, Tayside, the Highlands and Islands and the central belt. But in Dunbartonshire, Ayrshire, the Lothians and the south colleges score below the national average.
The report acknowledges that low participation might mean competition from private trainers, community education and in-company training. Strong school performance has also led to more young people going directly to university.
Tom Kelly, chief officer of the Association of Scottish Colleges, warned that enrolment figures include very short, taster courses and were not based on "substantive" programmes of study.
Leader, page 18