Passengers and staff on Fullers360 ferries in Auckland can now access free tampons and pads onboard.
All of the company's female bathrooms in its five support offices, which includes the Waiheke Bus Company, will also have free period products available.
It has partnered with Dignity, which provides free period products, to stock them.
Fullers360 said it is the first tourism and public transport provider in New Zealand to do this.
It said 42 per cent of its marine crew are menstruators, so the initiative was a "no brainer".
Taking part in Dignity's 'Buy-one, Give-one' initiative, Fullers360 said for every period product it purchases, Dignity provides another for people without access to them.
Natasha Colville, Fullers360's crew development manager, said Dignity's branding and values had aligned with theirs.
Fullers360 and Dignity had been working on the initiative since mid-last year, she said.
"It’s about making it known to people that menstruating does happen every month and that we want to support that by having the products there," Colville said.
She said menstruators at Fullers360 can often be "caught out", so the dispensers will take away that element of worry.
"There are days when you’re on the ferry for your shift without any access to a nearby pharmacy or supermarket; or you may be stationed at a DOC protected island and there’s nowhere at all to get what you need."
"It’s also about the community being able to have these products on hand when they need them... we’re prepared for them," she added.
In a statement, Mike Horne, Fullers360's CEO, added people should have access to period products like they do any other basic bathroom amenities.
"Our people and passengers deserve to have access to period care products in any bathroom just like they can access toilet paper and hand soap. We’re incredibly proud to be able to provide free period care and encourage people to take what they need," he said.
"Our hope is that by providing free products onboard and in our office bathrooms we can help close the period equity gap in New Zealand."
Anika Speedy, Dignity's general manager, said Fullers360 was addressing a need in the community and through its initiative had made a "huge investment" in both the community and its staff.
She explained Dignity's 'Buy-one, Give-one' initiative was about addressing period poverty and period equity, which is all about having equal access to hygiene products.
About 300 boxes of period products have been provided to Fullers360 to kick its initiative off.
Speedy is encouraging more businesses to jump on board, as demand for its services had "exploded" in the wake of the Covid-19 pandemic.
To date it had gifted more than 546,780 period products to people without access, she said.
Not all of Fullers360’s ferries have bathrooms onboard. On vessels which do, passengers are advised to look out for a period care dispenser with free pads and tampons inside. There is at least one onboard.