Free period products in schools will be rolled out at 15 Waikato schools next term, with all state and state-integrated schools able to opt-in from 2021.
Budget 2020 put $2.6 million towards the roll-out.
Prime Minister Jacinda Ardern said today it was a step towards combating period poverty in New Zealand.
"Nearly 95,000 nine- to 18-year-olds may stay at home during their periods due to not being able to afford period products," she said in a statement outlining new details of the initiative.
"By making them freely available, we support these young people to continue learning at school."
Minister for Women Julie Anne Genter said periods were a "fact of life for half the population and access to these products is a necessity, not a luxury".
1 NEWS first reported the issue of students missing school because of "period poverty" in 2016.
Research released by KidsCan estimates 20,000 primary, intermediate and secondary school students were at risk of 'period poverty', meaning they are unable to or struggle to afford sanitary products.
Last year, Positive Periods calculated the cost of rolling out period products at a minimum scale, estimating it would cost $4.5 million to provide pads and tampons at targeted, low-decile schools.
They found the cost of a medium intervention - the same model, but including all New Zealand primary schools and compulsory menstrual health education - would be $6.9 million.
The 'maximum intervention', costing $11.7, million would see the same model as the medium intervention, but also provide menstrual cups and period underwear. Under this model, 25 per cent of products provided would be reusable, estimated to lower costs in subsequent years and reduce disposal needs.