The Avon-Maitland District School Board is advising parents that all its schools would shut down if a one-day walkout by teachers and education workers goes ahead Wednesday.
A letter explains the action would only happen if the Ontario Secondary School Teachers' Federation can't reach a tentative contract agreement with the province by then.
The letter sent home to parents Friday says the shutdown would affect all high schools and elementary schools in Huron and Perth Counties.
Director of Education Lisa Walsh adds that the move would be necessary, because there wouldn't be enough supervision to ensure student safety.
All out-of-school activities including field trips scheduled for Wednesday, would also be cancelled.
The closure would not affect child care and Early ON programming, while community use of schools permits would be honoured.
Schools would return to normal operation on Thursday.