Researchers are calling for Kiwi kids to be taught about menstruation at a younger age

A University of Otago study has found more than half of girls have their first period before they reach high school.

Public health researcher Sara Donovan says many kids aren't educated on sexual and reproductive health until high school.

She says these results show this needs to change.

Donovan says it should start at primary school age - and sanitary disposal bins should also be made available to younger girls.