Some school principals say many schools are considering a hike in parent donations next year and cutting teacher aide hours, as they respond to a freeze on core school funding.
More than 300 school principals responded to a survey by teacher unions.
About 40 percent of school principals said they were considering cutting back on the hours of teacher aides and other support staff next year.
Thirteen percent said they were looking to increase parent donations.
The president of the teacher union NZEI, Louise Green, said the survey showed it was students who miss out when school funding was frozen.