There are about 9000 aides and support staff across primary and secondary schools in New Zealand.
Schools pay support staff from their operational grants, which were not increased in the 2016 Government Budget.
The teachers' union wants an increase in operational grants, and says schools should not have to juggle budgets - that will lead to cuts in hours for other staff, and that's not fair on schools.
Teacher aides work with kids who have learning or physical disabilities, or a point of difference, like ADHD or autism.
Without an aide, a different child struggles, and so does their teacher. Because struggling kids take up more of a teacher's time, which impacts on other children's learning.