Labour's taking another swipe at the government at its stance on tax cuts.

The party's Finance spokesman Grant Robertson is accusing National of making a mockery of the Budget process by dangling the promise of cuts, but not including them in the Budget, in a business speech delivered in Wellington this morning.

He said the Government needs to come clean and say if cuts are on or off - otherwise the uncertainty will make the government accounts obsolete and irrelevant.

"If you really believe they're the right thing to do for New Zealand, cost them properly and put them into Budget 2017, rather than dangling them about in an election campaign as a promise from Neverland."

Mr Robertson said they would re-establish a tax working group, if they win the next election, to test the current system.

He said they won't take a capital gains tax to the next election, but signals it's not off the table down the track.

"Clearly, that has to be on of the options a tax working group would look at."

And Mr Robertson said Labour will take a look at tax thresholds and bracket creep, thought he sees other areas as higher priority.

"We have huge pressures in health, education and housing that we need to spend that money on."

Mr Robertson said health-cost inflation rises at a faster rate than the rest of the economy, and the population's clearly growing and getting older.

"This is the figure that we've calculated based on previous years that we believe the government needs to invest, just to stand still. That's the really important thing, this is a figure of $600 million just to stand still, let alone the 1.7 billion that's already gone."