During the past five years sixth-form colleges have shed 5,000 full-time staff and recruited another 9,000 part-timers.
In order to cut costs, colleges have also been dismissing staff and re-employing them on different contracts for less money.
"Colleges have threatened to sack staff unless they were prepared to accept this," said Joe Boone, assistant secretary for the National Association of Schoolmasters Union of Women Teachers. We have tried to protect salaries for the first couple of years."
In FE colleges many staff are being issued with contracts which do not extend initially beyond the autumn term.
Sue Berriman, the national FE negotiating secretary for the lecturers' union NATFHE, said: "If students are not retained who arrive in September, then lecturers are out of a job.
"How can they give confidence to their students?
"Students need a lot of encouragement that you are going to look after them to the end of the course. The fact that teachers cannot guarantee this increases the stress; they cannot be as professional as they want to be."
In 1995-96 the chief inspector's annual report for the Further Education Funding Council remarked on this.
The report stated that continued fear of redundancies was sapping staff morale.
It also said that the increasing reliance on part-time staff, who did not tend to become involved in in-service training, appraisal or student support and guidance, was not always in the best interests of the students and was threatening standards.