ACC Minister Nick Smith says an "improved performance" by the corporation means levies could be reduced in future but Labour and the Greens says that money was saved by slashing support for accident and abuse victims.
Dr Smith said reforms had put ACC "back to a path of financial sustainability". Part of the improvement had seen $638 million of taxpayer funding over four years freed up from the non-earners' account, which covered injury claims from people outside the paid workforce including students, beneficiaries, retirees and children.
That account is funded by taxes and Finance Minister Bill English said that money would contribute to the Government's wider programme to return to budget surplus as soon as possible.
Dr Smith said levy reductions were possible later in the year.
"The formal process for ACC is firstly to determine the amount the taxpayer needs to fund in that non-earners' account -- that's where there's very good news.
"How that will flow in to the other accounts, we'll have to wait later in the year until we see the actuary results of the projections for ACC's future liabilities."
The savings come after ACC reforms in 2009 that included a reversal of entitlement extensions, an increased emphasis on improving rehabilitation, cost-cutting, and increased levies.
Labour's Chris Hipkins said the Government had deliberately undermined confidence in ACC.
Less than a month after National became Government it said it discovered a $1 billion hole in the ACC budget and increased levies.
"They talked up a financial crisis when there wasn't one, they eroded entitlements for ACC when they didn't need to and hiked levies when they didn't need to do that either," he told NZPA.
"It's clear their agenda is to soften the scheme up to privatise it."
Mr Hipkins said cuts were unnecessary and had a human cost. He accused the Government of "playing with the figures" to manufacture a crisis that didn't exist.
Green Party ACC spokesman Kevin Hague said cutbacks had hurt sexual abuse victims, people suffering hearing loss and accident victims with knee and back injuries who were being denied medical support.
"This Government has been deliberately undermining ACC and is making it harder and harder for accident victims to get support, and they now have the heartlessness to call it a success," he said.
"John Key's Government needs to stop cost cutting by denying accident victims surgery. These cut backs are forcing accident victims to go to the courts to get ACC support, where justice is delayed -- often for years.
"There was no financial crisis in ACC. It is now abundantly clear that a 'crisis' was manufactured by the Government to undermine and privatise ACC. There is no excuse for cutting support to accident victims."
Dr Smith said ACC's costs had increased sharply every year and the Government had worked very hard to get the costs under control.
That had given the Government "some room for pulling back the level of taxpayer funding, as well as ultimately having look at whether there's room for reducing those levies".
Dr Smith last year said the Government wanted to open ACC's workplace cover to private competition. He announced a decision in principle but it would not happen until the Government had sought a public mandate at this year's general election.
NZPA