Free and cheaper doctor visits were announced in Budget 2018 and from December 1 up to 540,000, Community Services card holders will see the cost of visiting the doctor fall by an average of $20-$30.
56,000 13-year-olds will also become eligible for free primary care.
Prime Minister Jacinda Ardern says cheaper doctor bills means more people getting the care they need, when they need it.
"In a country like New Zealand cost should not put people off going to see the doctor when they're sick. I'm proud that, from tomorrow, the government has made cost much less of a barrier to hundreds of thousands of Kiwis.
“Extending free doctors' visits to every child under 14, is a big step towards that goal."
Health Minister David Clark says more than half a million people choose not to go to the doctor because they couldn’t afford it.
"Not only will cheaper doctors visits mean more people will be able to afford to get the care they need, that will mean many health issues can be identified and treated early before they become major problems requiring hospital treatment.
"So far more than 80 percent of general practices have signed up to deliver cheaper visits for their patients. I want to thank the primary health sector for their hard work preparing for the roll-out of this policy, which will make it easier to access their valuable services over time," says Clark.