Lecturers were urged this week not to apply for jobs at a college that announced its 16th round of redundancies and restructuring this year.
Natfhe, the lecturers' union, has taken the rare step of "greylisting" Newcastle College, the biggest in the north-east, with 40,000 students and more than 2,000 staff.
The union is also asking its members to refuse to act as external examiners or moderators or to attend conferences at the college unless they are contractually bound.
Central to the dispute is the college's insistence that staff sign new contracts which the union says will mean longer hours and less pay. As a result, staff at the college have already staged seven one-day strikes this year.
Iain Owens, Natfhe's regional office for the north-east, said: "This is the first time in my 10 years as a full-time union official that we have taken this step.
"It is a drastic step to take but it reflects the seriousness of the collapse of proper industrial relations and the college's unwillingness to negotiate.
"It is not just the latest round of redundancies but the introduction of this non-negotiated contract that has forced us into taking this rare step.
"This contract is by some margin the worst of any college in this area and our members have been given until October 22 to sign it or be sacked."
The greylisting, the union's politically correct term for blacklisting, was first decided at the union's annual conference in May but had been suspended while talks with the arbitration service ACAS took place.
Jackie Fisher, Newcastle's principal, said she was shocked by "Natfhe's inaccurate portrayal of staff changes at the college."
She said: "For some reason, Natfhe has chosen to present a very negative picture of the college but this is not borne out by the statistics.
"Over the past academic year, not a single member of staff has been made compulsorily redundant. Only six staff have taken voluntary redundancy and 26 have been redeployed into similar posts and in some cases promoted posts. In the same period we have appointed over 250 additional members of staff.
"Natfhe are always fully involved and consulted in this process and are generally supportive of the approach we take.
"As Natfhe officers are aware, and the figures show, we place a high priority on identifying alternative job opportunities within the college for any staff involved in a restructuring."
She said there is a re-training programme for those who move to new jobs within the college.