The Education Review Office is encouraging schools to use a cohort entry system for five-year-olds, as opposed to have them start school individually on their birthdays.
It says five-year-olds appear to benefit from starting school in groups, although just seven percent of schools currently use cohort entry. This means new entrants start school on specific days each term.
The review office says most of the teachers and principals it surveyed say children are happier and settle into the classroom faster if they start school as part of a group.
Most principals say children's learning is better under cohort entry, though just half of teachers agreed that's the case.
The review office says New Zealand is the only OECD country that lets children start school on their fifth birthday.
ERO deputy chief executive Ruth Shinoda told Morning Report more schools should consider using the cohort system as it had demonstrated significant benefits for all concerned.
"They've been finding surprisingly good results in terms of being better for the children, better for the families and better for teachers too," she said.
"Under cohort you join in smallish groups and what the schools have done - nine out of 10 who did it stick with it, because they found that children learn better. They settle in and the transition is easier.
"Families say they have stronger friendships, so the families feel better and the teachers have got more time to teach because they are able to plan better.
There are no significant issues for most early childhood centres who have children waiting for younger children to reach five years of age so they can join the school cohort, she said.
"It really depends on the early childhood centres. So the small centres, the wait isn't going to be big, maybe a couple of days or a few weeks. The bigger centres, it means that they may have a few more older children so they may need to adjust their practices a bit. The main thing with early childhood centres is the schools should talk to them and then together they can plan."
She said it was early days for the initiative, which should remain voluntary, but should certainly be encouraged.
"Even though they're finding great results, we need to know a bit more. So we would just encourage schools to think about it, particularly post-Covid, where teachers have got a lot on and children are finding the transition to school quite tricky."