Health Minister David Clark is dampening expectations on when Kiwis will get access to cheaper GP visits.
Labour promised to cut GP fees by an average $10 from July 1, but has admitted that might not happen.
"We're going to have to phase in some of these initiatives. There's no doubt about that. I'm not going to skate around that," Dr Clark told TVNZ's Q+A on Sunday morning.
He declined to give a date when the price cuts would happen, only saying it was still Labour's intention.
"Last year, over half a million New Zealanders couldn't afford to go to their GP. One in four adults in New Zealand now cannot afford to go to their GP in any given year for reasons of cost."
National health spokesman Michael Woodhouse called it a broken promise.
"That to me is a clear admission that the promise Labour made to New Zealanders will be broken.
"More than $1 billion was allocated in their fiscal plan to fund this promise," he said.
"If, as the Heath Minister has claimed, he is absolutely committed to the principle of bringing down the cost of going to the GP and the funds were allocated in their fiscal plan, why is it now not happening? The answer is that the Government has considerably over-promised and is now backtracking by breaking a key campaign promise."
He said the Government has racked up a "woeful litany" of broken promises in just six months, including "the manufactured Middlemore crisis, raising massive expectations for nurse pay increases he won't now meet, the debacle of the air ambulance tender, inertia and an unnecessary inquiry in mental health".
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Labour has said the outgoing National-led Government left it massive shortfalls in health funding, which led to the Middlemore crisis, over-subscribed mental health services and underpaid staff.