Terry Melia, further education chief inspector, warned the majority of colleges were still far from ready for the hands-off inspection regime now being planned.
He told The TES that too many institutions were complacent. "They are turning a blind eye to their weaknesses," he said.
His comments reinforce the conclusions of his annual report for 1994-95 in which he said some colleges were "viewing their own performance through rose-tinted spectacles" and allowing standards to slip.
Dr Melia's latest offensive against complacency comes as he moves towards a new inspection strategy which will put the onus on colleges.
Details of the proposed new framework, released to The TES this week by Dr Melia, show that the present system of inspection visits covering every element of college provision would end once the first cycle finishes in 1997.
Instead, colleges would assess their own performance. Leaner inspection teams would be used to validate their findings.
Colleges judged to be particularly "self-critical institutions which set and achieve high standards" could be allowed even lighter-touch inspections. They could apply for accreditation by quality assessment committee at the Further Education Funding Council. They would become centres of excellence helping spread assessment good practice to neighbouring institutions.
Colleges found to have serious problems or to be poor at finding faults would face an old-style full inspection. Institutions whose standards were found to be slipping would be brought back into the regular inspection system.
Dr Melia said a key aim of the changes was to bring the college inspection framework more closely into line with the systems run by others such as the Office for Standards in Education and the National Council for Vocational Qualifications.
There would be more emphasis on curriculum areas, teaching and learning, quality assurance and students' achievements, including qualifications. Data gathered using the Individualised Student Record - a detailed statistical record of every student's progress - is expected to be used by inspection teams.
The chief inspector said colleges faced tough challenges in the new regime, but insisted they had time to make themselves ready.
He said: "No one is ever going to be ready unless we give them the opportunity. Colleges have really got to be much more self-critical and we have until 1997 to lead them up to that."
Publicly admitting weakness required maturity, he added. "It is easier to do it if you are pretty successful, but when there is a lot wrong it is much more difficult to address."
A working group including representatives of colleges, employers, industry leaders, TECs, governors and government departments will devise the new framework.
Michael Austin, principal of Accrington and Rossendale College and a member of the working group, said colleges' experience using internal audit teams to assess their performance had proved salutary.
But he added: "There is no doubt the sector is not ready for self-assessment yet."