THE Baillieu government will send strike breakers into schools on Thursday as 30,000 teachers, principals and support staff walk off the job for better pay and conditions.

The Education Department has asked former principals and casual relief teachers from agencies to supervise children who show up.

The department confirmed that agency staff would step in to ensure that principals fulfilled their duty of care.

''The department is supporting school principals to fulfil their duty-of-care requirements of ensuring that all students who attend school tomorrow will be safe, cared for and properly supervised. This may include the hiring of agency staff.''