The Green Party has pledged to make public transport free for eligible groups and cap bus and train fares at $2 for everyone else.

It says its transport plan offers fast, frequent and affordable services.

Under the Greens' policy, public transport would be free for children, students, apprentices, Community Service Card holders and Total Mobility users, while everyone else would pay a maximum fare of $2.

It would also build mass rapid bus and light rail services in Auckland, Wellington and Christchurch, offer more frequent inter-regional bus services, strengthen rural bus services and allow councils to pedestrianise more inner-city areas and increase safe walking and biking spaces.

The party has also promised overnight passenger trains from Auckland to Wellington, as well as bringing back the Southerner between Christchurch and Dunedin and extending Te Huia to Tauranga.

"In the middle of a fossil fuel crisis, these common sense investments will save New Zealanders money, stress and time," co-leader Chlöe Swarbrick said. 

"It'll cut emissions and improve quality of life."

Swarbrick and transport spokesperson Julie-Anne Genter addressed media in Auckland on Sunday from outside Maungawhau City Rail Link station.

Swarbrick referred to the more than a million trips that have been taken on the CRL since it opened last month.

"What that tells us and shows us so clearly is that when we build transport infrastructure that makes it easy, affordable, and even fun to get around, people will use it.

"But right now, too many New Zealanders are driving around with the fuel light on, hoping and praying that petrol prices will drop," she said.

Swarbrick said the government could not control oil shocks like that caused by the Middle East war - but it could make investments that reduce the cost of living and reduce dependence on fossil fuels.

She described the party's plan as "straight up common sense".

Swarbrick said meaningful change could be made immediately, but some parts of the plan like light rail networks could take a decade or so.

The major investments would go through the Infrastructure Commission's assurance process, she said.

The entire plan would cost around $23.9 billion: $21b for mass rapid transit and rail investments, $1.3b for capped and free fares, $75m for electric buses, $290m for councils to expand walking and biking spaces, $824m for public transport improvements and $406m for inter-regional buses.

"What we are proposing today is to meet the needs not only of our immediate cost of living crisis, but also our medium and longer term needs to build infrastructure that is fit for purpose for the future. Yes, that will cost money," Swarbrick said.

She cited the Greens' wealth tax as a way of paying for some of it, but said the party's full fiscal plan would be laid out in the next few weeks.