Labour leader Phil Goff warns his party's tax announcement on Thursday will include tough decisions aimed at getting the public finances back into surplus.
But Finance Minister Bill English has accused the main opposition party of having a tax and spend policy that will put economic growth at risk.
Mr Goff refuses to disclose details of the package even though its worst-kept secret is that it will include an extended capital gains tax.
He says the package will be a responsible one and most taxpayers will be better off.
But Mr English says Labour is proposing to tax more and spend more.
Mr English is sensitive, though, to suggestions the National-led Government missed an opportunity to introduce a capital gains tax in response to the Tax Working Group's report.
The Government got the tax package it introduced last year about right, he says.