Labour is claiming the government has a secret agenda to increase school class sizes.
It's citing a Treasury briefing paper to ministers which says education funding needs to be used more efficiently and changing the teacher-pupil ratio is a way of doing that.
The paper was released on Thursday and Finance Minister Bill English reacted by not ruling it out.
The government has told all its ministries they have to find ways to cut costs during the next three years.
Labour's state services spokesman, Chris Hipkins, says the government is using the Treasury as a front for its own intentions.
"They code this by talking about `consideration of teacher-to-student ratios' but it can only mean one thing - more kids in each class," he says.
"Cheaper might be better when it comes to buying pens and papers but our children's future should not be at the mercy of distorted policies to cut budgets no matter what the real long-term cost is."
NZN