Pregnant women - including the Prime Minister - have been asked to donate the sanitary products they would have used for the nine months they don't get a period.
For International Women's Day today Cambridge woman Franny McInnes is collecting menstrual cups, pads and tampons to distribute to girls in "period poverty" who can't afford sanitary products.
Minister for Women Julie Anne Genter, who is also pregnant, is supporting the campaign.
Menstrual cups, which are reusable and last up to 18 years, are being toted as a solution to period poverty.
Labour MP Willow-Jean Prime knows 14-year-old girls who've never had a period. They're on contraception to prevent them as their families can't afford sanitary products. Others resort to using newspaper, telephone books and rags to make do.
Some girls regularly miss school each month when they menstruate. If a girl missed a week a month of school that equated to a whole term of lost learning. Education is a human right and girls were being deprived of it, Prime said.
"We were really shocked by that level of poverty in our community … I really found that very very sad."
McInnes, who owns an online maternity store, is always interacting with pregnant women - she decided to use her networks to help.
"There were 59,610 births in New Zealand in 2017," she said.
"If we have a similar number of births in 2018, that works out to over half a million packs of sanitary products women aren't using during the nine months of pregnancy."
Genter, who is due in August, was passionate that periods should not be stigmatised and was looking into what government support there was to provide sanitary products to girls.
"Sanitary products are not a 'nice-to-have', women need them for their health.
"I haven't needed to use my menstrual cup for a few months now, and I would love to support this initiative by donating sanitary products to women and girls who do need them."
Prime's sister Season-Mary Downs had started using a menstrual cup and found it a "life changing, liberating, empowering" way to manage her period.
A menstrual cup costs on average between $25 and $60, they last up to 18 years. Whereas 18 years' worth of tampons will cost a woman around $4320.
From September last year the sisters raised close to $25,000 and have given out 1100 menstrual cups in their Kawakawa, Moerewa and Kaikohe communities, with more on the way.
Over the lifetimes of these 1100 women, they would save more than $10 million and prevent around 170 tonnes of sanitary product waste from going to landfill.
To normalise it, Prime and Downs focus on "cup connectors" spreading the message to their daughters, aunties, girlfriends and other women. They distribute the cups for free along with a one-on-one chat about how they work.
Prime was initially a bit prudish talking about the cups. But now finds herself talking periods on every street corner.
"We know the menstrual cups are having a profound effect on our whanau. This is life changing for women.
"In order to get to the young women the girls at school we need to convert the mums and aunties as it is likely to be them that have that conversation with them."
Prime Minister Jacinda Ardern, who is currently in the Pacific, did not respond to queries on whether she would donate to the campaign.
But McInnes was not disheartened. She added that donating is open to everyone, not just pregnant women.
McInnes will collect new, unused menstrual cups and unopened packs of disposable sanitary napkins and tampons from March 8 to 31.
The products can be posted to Pass On Your Period, c/- Breastmates, PO Box 830, Cambridge 3450, or donations can be made to Sanitary Products in New Zealand Schools here.