There is increasing concern among government advisers that the skills strategy being developed by the Department for Education and Skills could neglect other learners, including the elderly.
The National Institute for Adult Continuing Education wants to see 3 per cent of local Learning and Skills Councils' budgets earmarked for courses which fall outside published targets.
Alan Tuckett, director of NIACE, says room needs to be found for what he calls the "three Cs" of culture, citizenship and community development.
He said: "There comes a time when we have to put aside our advisory role with government and take on an advocacy campaign to defend vulnerable groups and activities.
"It is clear the Treasury is still wedded to the targets, but it should also take account of the groups who are likely to be excluded if local LSCs devote all of their funds to meeting targets and ignore everything else.
"The figure of 3 per cent is not enough, but you have to start somewhere."
He will put his ideas to ministers in the summer before they put the finishing touches to the national skills strategy. The idea of such a quota may be resisted by the LSC, which sees meeting targets as the priority.
Bryan Sanderson, chairman of the LSC, said: "There are some very difficult decisions to make. There is only one cake.
"For me, the top priority is to get back the people who are outside learning."
The latest DfES bulletin on the progress of the skills strategy shows that fees for some of these non-targeted adult learners could be increased from the current recommended level of 25 per cent of course costs.
Colleges could be forced to raise fees to increase the number of students in other areas.
Winners under the new strategy are expected to be adults without level 2 qualifications (equivalent to GCSE grade C or above), people under 30 taking level 3 (A-level equivalent), and adults taking level 3 qualifications in skills shortage areas.