The Educational Institute of Scotland said it was on "red alert" this week in anticipation of job losses at the 12 further education colleges which have suffered cuts in Scottish Office funding.
This follows the continuing dispute at Borders College, where four lecturers are appealing against compulsory redundancy notices.
The EIS's College Lecturers' Association and the Scottish Further and Higher Education Association say that Mark Craig, the college's business and corporate manager, assured union officials at a meeting to discuss job losses that "full consideration" would be given to the issues raised.
The redundancies were announced just one hour and 20 minutes later.
Bob Murray, the college's depute principal, said that the meeting with Mr Craig was "informal in scope as national officials of neither union hold any formal role in locally negotiated agreements with college staff members".
Mr Craig wrote to Marian Healey, the EIS's further and higher education officer, denying accusations of bad faith. "I played no part in the final selection process which was being considered by college management independently of my discussions with you in Edinburgh," Mr Craig stated.
The union is particularly concerned that union activists may be targeted. Lesley Donaldson, who sits on the CLA's national executive, and Mary Stewart, SFHEA branch secretary at the college, were both laid off. Penny Packham, another CLA executive member, was forced out of Jewel and Esk Valley College last summer.
Ms Healey said: "It is something which colleges do, although they always deny that they do it."
The Borders lecturers were told to leave the college "within hours", despite the college's redundancy policy which states that "employees will be given a reasonable amount of paid time off to look for other work or to arrange training".
The CLA also cites the case of a lecturer aged 61 with 12 years' service who was made compulsorily redundant by Glasgow College of Nautical Studies. The man was informed at 10.30am and asked to leave within two hours.
"This is a totally undignified and inhumane way of treating employees who have given dedicated service to colleges over the years," Ms Healey commented. The Glasgow college was hearing the lecturer's appeal this week.