The Green Party would make it free for everyone under the age of 19 to travel on buses, trains and commuter ferries.
A 'Green Card' would be created, which would also provide free off-peak travel for tertiary students and those doing apprenticeships.
Under the policy all people with a disability on a supported living benefit would also be eligible for free public transport.
The Greens' transport spokesperson, Julie-Anne Genter, said the policy would cost $70-80 million a year.
"That would buy about 1km of the Puhoi-Warkworth motorway, if we look at the announcement made by the National government for $10.5bn on a few highways - that's 100 years of free public transport."
Ms Genter said the cost of transport should not be a barrier to getting to class or going on a family outing.