Colleges have warned that they will be unable to introduce the radical exam reform proposed by the Tomlinson group unless they are given the same funding as schools.
The proposed diploma is designed to increase staying-on-rates, raise standards and reduce the burden of assessment.
It would include core areas of study including maths, communication and information technology. Students would also be able do a project of their own choice. Post-16 learners would be able to specialise in vocational areas as part of the overall programme.
Colleges and unions welcomed the proposals but both are concerned about its viability given current funding levels.
Judith Norrington, director of curriculum and quality at the Association of Colleges, said more resources are needed for salaries and the costs of administering the new qualification, which will take 10 years to introduce, initially alongside A-levels and GCSEs.
She said: "If you want to make it work you have got to look at how much people are paid. There's a 10 per cent gap between what each student brings in at a school compared with a college.
"Whether it will work depends on how long you can go on making use of people's goodwill. This is a particularly serious issue since colleges have about 200,000 more 16 to 19-year-olds than schools."
Apart from having the lion's share of 16 to 19-year-olds, further education also caters for increasing numbers of schoolchildren at 14-plus.
Ms Norrington said colleges have already proved better at providing programmes of study across a range of subjects, with lecturers accustomed to comparing notes about individual students across disciplines, much in the spirit of what is planned under the new diploma.
Mr Tomlinson's report says, "we do not pretend that our proposals will be cost-free". But there is no suggestion that further education is seen to have a special case for more money.
It says: "Expectations of teachers within the new framework must be matched by sufficient support for schools, colleges and training providers to ensure that all aspects of teaching, learning and assessment are properly resourced."
Paul Mackney, general secretary of Natfhe, the lecturers' union, said:
"Welcome as these reforms are, teachers and lecturers have already suffered from decades of 'change fatigue'. We want assurances that the reforms will be adequately funded, gradual and steady - with those delivering the changes prepared and consulted every step of the way."
The diploma, if eventually adopted by ministers after the working group has completed its full report, will be available at four levels.
There will be an introductory "entry" level; a foundation level, equivalent to GCSE D to G; "intermediate", the equivalent of grades A to C, and "advanced", equivalent to A-level.
Mr Tomlinson's report, intended as a consultation document, will be followed by a final report with recommendations to Charles Clarke, the Education Secretary, in the autumn.