The Labour Party is pledging to spend nearly $300 million a year to make doctors visits and prescriptions free for children aged up to 13, pregnant women and the over-65s.
Pregnant women would also get free dental care.
Watch Labour leader David Cunliffe making the announcement at the party's election campaign launch in Auckland on Sunday
About 1000 people heard Mr Cunliffe speak at the Viaduct Events Centre on Auckland's waterfront.
The National-led Government extended free doctors' visits and prescriptions for children aged under six to all children aged under 13 from July next year.
Mr Cunliffe said Labour would make that take effect after the election, should it be able to form a Government.
He said under its policy nearly 40 percent of New Zealanders will be eligible for free doctors visits and prescriptions.
Mr Cunliffe said Labour was committed to progressively reduce health costs across the board as economic conditions allow, but its initial focus was on people with the highest health needs and health costs.
He said last year 250,000 New Zealanders did not get their prescriptions filled because they could not afford it.
"Those are people who went to the doctor, found to be sick, got a prescription and couldn't get treatment cause they didn't have the money - that is not the New Zealand that we believe in."
Labour estimates that providing free doctors visits, prescriptions, and dental care for pregnant women would cost $10.4 million a year.
It says providing free doctors visits and prescriptions for over-65s would cost $120 million a year.
Labour would also extend the Care Plus programme so that a further 250,000 New Zealanders with long-term health conditions can get free GP visits and prescriptions.
It estimates this extension would cost $90 million per year.
It is also pledging to invest an extra $60 million into primary healthcare.