The Association for College Management and NATFHE made unprecedented moves after separate stalled talks with employers.
Negotiations between the ACM and the Colleges' Employers' Forum, which resumed after failure to reach a settlement last week, broke down again when the two sides failed to agree on the management union's demand for a widening pay gap with lecturers.
ACM, which wants managers to be offered at least 1 per cent more than lecturers, accused the CEF of reneging on a principle it had agreed to in last year's talks, and said it would not rule out striking unless concessions were made. The moderate union is unlikely to break its strike duck, but members could work to rule or withdraw goodwill.
National negotiator John Bolton, principal of Blackburn College, said the union was "surprised and disappointed" at CEF's position. Managers were becoming increasingly disaffected, he said.
CEF chief executive Roger Ward said the package offered to the ACM - a 2.4 per cent pay rise with a commitment to urge colleges to meet the increase and also offer bonuses and corporate health schemes - was different to the deal offered to lecturers.
The CEF had "a great deal of sympathy" with the ACM but would be unlikely to offer anything further.
Meanwhile NATFHE, which was last week threatened with derecognition by CEF in national management spine pay negotiations, is recommending branches should consent to employers' demands to recognise an existing national contract for senior staff.
The union has always held out against the deal, which was drawn up in 1994 and has already been accepted by ACM. The CEF now says it will not negotiate with NATFHE on managers' pay unless the contract is recognised.
However, some in the union are describing the recommended concession as "a betrayal of management grade members" and insist it will not be accepted.