UPDATED 3.10PM The Prime Minister has said tax cuts aren't necessarily off his Government's long term agenda.

The Government has made it clear there'll be no tax cuts for next year announced in his Budget this month. Instead it's dipping into future new spending allowances to cover other costs, including debt.

John Key said tax cuts haven't been ruled out for next year, they're just a little more unlikely - but he said that doesn't mean they won't happen.

"So in terms of what we either might do in Budget 2017 or what we might campaign on if we're in the privileged position to get a fourth term, you'll just have to wait and see."

Finance Minister Bill English also isn't explicitly ruling out future tax breaks, saying the only conclusion people can draw is that on April 1st next year, there won't be lower taxes.

"Beyond that we have options because we have an improving fiscal situation, it's just that it's not sufficiently robust enough yet."

Labour MP Grant Robertson said the Government has backed off tax cuts because they've finally listened to the fact we need to invest in health, education, and in housing.

"The test for Bill English and the Budget is will he deliver on the promise of investment in health, education and housing, because that's what New Zealanders are looking for."

By ruling out tax cuts, the Greens believe the Government has admitted it has sold parts of the economy short.

Co-leader James Shaw sees it as an acknowledgement the Government has under-spent when it comes to paying down debt.

He said, particularly with the record immigration we're seeing in Auckland, our infrastructure is under increasing strain and we do need to spend for the future.

Meanwhile, the ACT party is accusing National of forgetting its voters. Leader David Seymour said income earners deserve a break.

"What was the point in voting out Helen Clark when the Nats are barely better on tax cuts and talk about introducing new taxes, then rule out cutting any tax?"

Mr Seymour said the Government should at the very least change the top tax rate.

He said anyone earning $70,000 a year is in the top tax bracket, but he's talked to many people who certainly don't feel wealthy enough to be classified that way.