Education staff at Irish medium schools and others not involved in this week’s strikes over pay are to be balloted on joining industrial action.
School support staff including bus drivers and classroom assistants began three days of strike action on Monday, and plan to take to picket lines again on June 3 and 4, in a dispute over pay and grading.
Those striking are members of Unite, GMB and NIPSA.
NIPSA has announced it is to widen a ballot on its members taking part in industrial action, to include those from voluntary, grant maintained, integrated and Irish medium schools, which have not been included in the recent strikes.
The union earlier this week warned that up to 20,000 staff could take part in further strike action in September.
Stormont’s Department of Education has said minister Paul Givan was unsuccessful in securing the £180 million required to implement the pay and grading review unions are demanding as a result of budget pressures.
NIPSA deputy general secretary Patrick Mulholland said: “This escalation in strike action is inevitable and disruption on a huge scale will take place in early September if a resolution is not found urgently.
“Stormont needs to secure the funding necessary to implement this agreed review quickly as our members have indicated they are not prepared to keep waiting.”
Mr Mulholland added: “Numbers called on to strike at the minute have been kept deliberately low but the impact has already been felt. A strike on the scale being planned for September will close schools across the country and the disruption will be huge. The money must be found to end this dispute.”
