If Labour is elected this year, the tax cuts National promised could be off the table.
Steven Joyce's first Budget as Finance Minister sees tax brackets shifted upwards, effectively giving most working Kiwis a tax cut.
Leader Andrew Little isn't ruling out repealing them however, should he become Prime Minister after this year's election.
"Now that we've got the current numbers from this year's Budget, we'll do our final bit of homework on that, as we put together our package."
Mr Little said Labour did support the changes made to Working for Families, which boosted family tax credits at the bottom end, but with a lower threshold and steeper abatement rate.
Labour didn't support the legislation that passed the tax cuts into law, but likely coalition partner the Greens did.
Mr Little isn't saying what Labour will suggest in their place.
"I'm not going to be drawn on any detail because we've had these figures for a matter of days - the Government's had eight months to work on it," he said.
"I make no apology for us getting on and doing the homework to work out what is fair and consistent with our principles."