One of the Government's support parties is challenging it to cut taxes now.
ACT's David Seymour says there's no reason to wait for next year's Budget and taxpayers shouldn't be "bribed and manipulated" with pre-election promises.
The Government last week posted a $1.8 billion surplus for the 2015/16 year, much higher than expected, and that's raised the prospect of tax cuts being offered in the 2017 election campaign.
Finance Minister Bill English is still being cautious, saying it's "a possibility" if the economy keeps growing.
Mr Seymour says don't wait.
"There's nothing in law that forces the Government to wait for a Budget to cut taxes," he said on Tuesday.
"The Government should cut taxes now, then campaign in 2017 on its record."
If the Government does cut taxes, the most likely move will be to shift the thresholds and help low and middle-income earners.
Mr Seymour has a simple proposal.
"Split the surplus into one third tax cuts, one third debt repayment, and one third new spending."
The Government's headroom for cuts will become clearer on December 8, when the Half-Year Economic and Fiscal Update shows the latest surplus forecast for the current financial year.