Natfhe general secretary John Akker joined a walk-out of staff after the futher education sector conference decided to hold a national ballot on striking over pay.
Staff complained that an activist at the behind-closed-doors session accused them of failing to carry out members' wishes.
The incident came after Mr Akker advised the stormy sector meeting that a national ballot, for a strike during enrolment, would be all but impossible to run before September.
The walk-out meant a two-hour conference session had to be abandoned. Proceedings resumed the next day after an apology.
Natfhe's further education pay claim is expected to be for a flat increase of Pounds 2,887 on all scales, which amounts to an average 14 per cent extra for the Silver Book contract holders denied a pay rise last year.