"The situation needed to be urgently addressed...today's announcement will go some way towards helping people be able to afford to visit a GP when they are sick."
About 1.4 million New Zealanders currently have the cost of visiting their GP capped at $18 through the "Very Low Cost Access" scheme.
Coleman said this will now be expanded by introducing $18 GP visits for all Community Service Card holders.
"This change means a family of three earning up to $60,000 per year will be able to access $18 GP visits, with children under 13 still able to go for free.
"As part of this policy, National will also expand the coverage of the Community Services Card to include everyone receiving an Income Related Rent Subsidy or Accommodation Supplement."
The policy is intended to roll out from July 1 2018.
The expansion of the Community Service Card will mean 350,000 more Kiwis will receive cheaper prescriptions, free emergency dental care and free glasses for children, as well as the $18 capped GP visits, Coleman said.
"These changes will increase the total number of New Zealanders who can access either free, or very cheap, GP visits to 2.5 million, at a cost of $380 million over four years. The cost will be met from the 2018 Budget operating allowance."
Prime Minister Bill English said the policy would make a real difference to the lives of New Zealanders, and came on top of the families income package announced as part of the Budget.
Coleman said the policy came after extensive discussions with GPs, and he believed it would be well received as a way to better target support.
"It is around intervening earlier, making sure people have access to the medical help they need before a condition might deteriorate... it also keeps people out of hospital beds."
The Community Service Card had to some extent been under-utilised, Coleman said, but was a "clean and efficient way of delivering the care where it is needed".
On criticisms that current support isn't targeted in the right way, Coleman said this would target support effectively. There would now be more than half the New Zealand population covered by low-cost doctor visit schemes.
People for whom cost was a factor in not going to the doctor could later end up in hospital, and today's policy would save lives, Coleman said.
There wouldn't need to be more GPs trained or hired as a result of the policy, he said, as there were enough doctors but the Ministry of Health and medical organisations were working on making sure doctors were available in rural areas, where some shortages could occur.
He was aiming to get at least 85 per cent of GP clinics buy-in to the scheme, and said the scheme would be generous.
"The existing low cost access scheme, the complaint from GPs has been that they are not in it... this is what they have been asking for."
Labour leader Jacinda Ardern said her initial reaction to the policy was anything that improved access to primary health is a good thing.
"I do want to have a little look at how they have funded it, to make sure it is fully funded...we will be making our own policy announcements in this area fully soon."
