Education unions are ramping up their fight against the Barnett Government's cuts to education.

Hundreds of school support staff, including education assistants, will walk off the job today and the teachers union is warning that principals and teachers could be next.

They are angry about plans to slash 350 education assistant jobs, 150 education department staff, freeze teacher numbers and cut specialist program funding.

Anne Gisborne from the State School Teachers Union says schools are already bracing for an extra 18,000 students over the next two years.

"The Premier and the Minister are saying and you can do that without any extra teachers, well I'm sorry but that's not going to be happening," Ms Gisborne said.

"We are not going to allow that to happen to our young children, and we're certainly not going to impede our own professional integrity by enabling that to happen.

"We will not be complicit in this gutting of public education."

The Director General of Education, Sharyn O'Neill says she expects today's action will cause only minor disruptions to school schedules.

"Schools are open, students should be coming to school, there might be some changes to programs but if you're uncertain, please call your school and check for yourself so that you know what the arrangements are," she said.

"I understand the union has a role to play but my interest is kids, their learning and getting on with what, that's what we do best."

Kylie Catto from the WA Council of State School Organisations, which represents parents, is urging the Government to reconsider its position.

We would encourage the government to engage in conversation that reaches a better outcome to avoid any potential further industrial action and any further impact on students in schools.

The State Government is standing firm and says its decision will not be reversed.