A bill that will allow children to start school at the age of four is set to pass into law this week.
The Education Amendment Bill will have new entrants starting school at the beginning of the term closest to their fifth birthday. This will replace the current system, where a child usually has to wait until they turn five.
Education Minister Nikki Kaye says it would still be optional for parents.
"Whether a child is ready to attend school just before they turn five years old, or even nearer their sixth birthday, is a decision that parents and teachers are in the best position to make.
"I don't think it is unreasonable to allow parents the option to let their children start at school a maximum of eight weeks earlier than their fifth birthday."
But the New Zealand Education Institute (NZEI) isn't impressed. They're one of many education sectors that have made submissions to Parliament against the bill.
President Lynda Stuart says there's no evidence to show it's a good idea.
"It's actually been well-celebrated that children start on or around their birthday, almost like a rite of passage I suppose - that special day of starting school when you turn five."
Chris Hipkins, Labour's education spokesman, says the plan doesn't take into account the best interests of the children.
"I think children change and develop so rapidly when they're very young that a matter of four or five weeks is a big difference for a child," he told The AM Show.
"Let's let children be children, and let's not push them into starting school too early."
Ms Kaye says starting children in groups at the beginning of each term makes it easier on them.
"There is evidence that starting school alongside other children leads to those children establishing stronger relationships and having a smoother entry to school life."
NZEI former president Louise Green says evidence from overseas suggests otherwise.
"Countries that do really well actually start children later than we do at six of seven. Five is already pretty early to start formal learning."
Ms Green says starting 'formal learning' earlier suggests early childhood learning centres are being unappreciated.
"What does 'ready for school' mean and what are we saying about our early childhood learning centres? I mean, our early childhood centres do an amazing job with children. Those teachers understand child development.
"You need to ask why this has come forward. It does sound mostly about being administratively easy for schools."