Prime Minister Bill English says tax cuts are on the table - but he refused to make any promises.
He says if tax cuts are announced in the next budget they would take effect on April 1, 2018. "We would follow the normal cycle."
He told Guyon Espiner any tax cuts would be looked at in the context of other demands, like pressure on public infrastructure.
Mr English said lower- and middle-income earners were a priority.
"We're not putting forward tax cuts as some kind of sugar shock.
"It's just over time, if you've got a growing economy and surpluses you can, through a variety of mechanisms, lift incomes."
There were "a lot of choices" on how to raise household incomes, he said, but would not specify which measures.