The Education Minister isn't making any promises to reduce primary school classes.
National's leader Simon Bridges said a priority of a government led by him would be to reduce class sizes.
Teachers said the current ratio should be reduced from 29 students per teacher to 25.
But the minister, Chris Hipkins, said a reduction in class sizes would be very expensive.
He told TV3's Newshub Nation he would like to discuss with teachers whether this should be prioritised over other ideas.
"It's very expensive to make even a modest change to class sizes and I think that's something we want to talk to the teaching profession about," he said.
"Is that the highest priority for them or are things like more classroom release time a bigger priority?"
Mr Hipkins also said he had commissioned new research on the age mix of teachers.
Currently the average age of primary school teachers is 57, with large numbers of teachers quitting the profession within five years of starting.
And there are fewer training as teachers than in the past.
Mr Hipkins said he had asked for research to be done on future needs of teachers and the demographics.