Parents at Illawarra public schools have been asked to bring their children to school one hour later on Thursday.
NSW public school teachers will stop work on December 5 to vote on a proposed industrial agreement with the NSW Department of Education.
As a result there will be minimal supervision for the first few hours of school.
Teachers have been asked to arrive at school by 8.30am for an 8.45am meeting to discuss a new award covering salaries and conditions
It is understood that schools that have already planned an event will be exempt but other schools will have minimal supervision until the close of the meeting, which is expected before 10.30am.
A spokesperson for the NSW Department of Education said schools will be open on Thursday and all students will be supervised during the NSW Teacher's Federation meeting.