Mr John White is now the clear favourite to succeed Mr Charlie Lennon as general secretary of the ASTI after he was appointed acting general secretary at the weekend.
Following a meeting of the ASTI's executive on Saturday, a motion to install Mr White in the role was passed by a majority of those present.
The post of general secretary is not likely to be advertised until May and might not be filled until the autumn, after a sub-committee of the executive was set up to work out what the specific criteria of the post should be.
The committee, which was established after it was agreed that the ASTI was not yet in a position to select and recruit a general secretary, is expected to consult widely with the membership of the union.
Among the issues it is likely to address are whether the general secretary should be offered a fixed-term contract of three to five years, and at what level his or her remuneration should be set.
Eventually, a second committee will be set up to interview and select the correct candidate for the job. This will probably take place following the ASTI's annual convention in April.
Mr White is regarded as a moderate figure within the ASTI, with one senior member describing his approach since Mr Lennon's departure last November as "completely honourable".
He is seen by many in the ASTI as having done an excellent job as interim general secretary.
However, others within the union have warned of a desire among its membership for a more radical voice as secretary general.
In recent weeks, there has been growing speculation that this might include former president, Ms Bernadine O'Sullivan, although she has so far refused to comment on the matter.
Mr Lennon left the €100,000-a- year post of general secretary last November after an agreement was reached on a €200,000 settlement.
This followed allegations made against him by the ASTI treasurer, Ms Patricia Wroe, that he had made bogus expenses claims, a charge he vehemently denied.