The Scottish Secondary Teachers' Association was thrown into disarray earlier this week after it terminated general secretary Sheila Mechan's contract 10 days after she had been suspended.
The next scheduled meeting of the executive committee of the SSTA, which has 8000 members, is not until October.
The union could discuss the issue formally at its annual conference in Peebles next week. But the vacant post would still have to be advertised and nominations would also be sought from inside the organisation.
An election would be held if there was more than one viable candidate.
The union has not had a permanent general secretary since Ann Ballinger retired in December 2012.
A spokesman said the decision was "regrettable", but had been taken in the best interests of the SSTA "given the immediate breakdown of a significant number of crucial working relationships".
It is understood there was a falling out between a number of key union officials after Ms Mechan started on April 7.
One of the problems is understood to have been a public forum for union members on the SSTA website where criticisms were made of the way the union was being run, to which Ms Mechan responded. Another source of conflict was Ms Mechan's proposal for a five-year strategy and she had also argued it was pointless to try to compete with the larger Educational Institute of Scotland union.
Ms Mechan, 55, said: "It would be accurate to say there were relationship difficulties."
A spokesman for the SSTA said: "The SSTA decided it was in the association's best interests to move quickly to resolve the situation."
Former acting general secretary Alan McKenzie is to resume the role while the recruitment of a successor is carried out.