Secondary teachers are set to be balloted on a new offer on pay for supervision duties which give teachers a payment of £1,000.
The offer is well short of what the teaching unions wanted, but the Department of Education insists it is the best deal available. Over 400 secondary schools face widespread disruption if the new offer is rejected.
The Teachers' Union of Ireland (TUI) will ballot members shortly on the offer.
Until now, teachers have performed supervision duties on a "voluntary" basis without any payment. The TUI is balloting members without a recommendation.
The ASTI's central executive is likely to put the issue out to ballot at a meeting today.
Today's meeting will decide whether any ballot should be accompanied by a recommendation from the central executive.
The key features of the supervision and substition deal worked out yesterday were :
A payment of £27 per hour for supervision/substitution duties.
A requirement that teachers perform 37 hours of supervision/substitution work in every school year.
Teachers can opt for further supervision work up to a maximum of 49 hours per school year.
Several of the 22-member ASTI standing committee were negative about the offer during a meeting yesterday. One member who was very critical of the union leadership - Mr Bernard Lynch - was expelled from the deliberations after a procedural row.
The Department of Education offer on supervision is short of the £2,000 annual payment sought by the teaching unions and it is not a pensionable payment. But one source insisted it represented a "very good deal" for teachers. "Teachers are getting money for something they already do for nothing", he said.
Last winter, school managers were forced to close schools for insurance reasons when ASTI members withdrew from supervision during the union's pay campaign. If the ASTI or the TUI rejects the latest offer, school managers could be left with no alternative but to close schools again.
However, one school manager said a determined effort would be made to recruit parents and others to do supervision if teachers refuse.
The atmosphere at the ASTI meeting was said to be highly charged, reflecting widespread grassroots anger about the failure of the union's pay campaign.
Negotiations with the primary-teachers' union INTO on the supervision issue have still to be finalised.
The union is insisting that any payment made to secondary teachers must also be given to primary teachers. The INTO executive will review its position after a further round of talks on Monday.