The ASTI have warned they will not accept compulsory redundancies on the back of a review of pupil teacher ratios in schools.

Some members of the union could be at risk of losing their jobs because they did not sign up to the Haddington Road Agreement and are therefore not protected from redundancy.

The Department of Education says that this may apply to a "number of over-quota positions in a small number of post-primary schools".

It adds "We have made it clear that these numbers may change, depending on information on enrolments and the September 2013 returns. This process is a standard one in the Department and occurs every year".

Those who are afforded protection by the agreement are re-deployed rather than made redundant, in the event that their school is deemed to be over-quota in annual checks.

Under the agreement the government has said teachers will be protected from losing their jobs if schools are found to be above the 1-to-28 pupil teacher ratio.

ASTI members wil be balloted for a third time over today and tomorrow, with a result due mid-December.

Pat King of the ASTI says teachers are aware of the implications.