Illawarra Catholic school teachers will strike on Thursday morning to draw attention to their negotiations with the Catholic Commission for Employment Relations.
Independent Education Union members from 31 schools in the Wollongong diocese, which stretches from Campbelltown almost to Batemans Bay and west to Bundanoon, will stop work for three hours.
Teachers and school support staff will dress in red and gather at Lang Park in Wollongong from 9.30am.
Spokesman for the Wollongong Catholic Education Office Tim Gilmour said while there may be some interruption to timetabled classes, all students would be supervised at schools if they arrived at the normal time and through normal transport arrangements.
Teachers are expected to return to class by noon.