While the parties seemed to be "keeping their powder dry", he did not expect there to be any major surprises in any pre-election tax policy, with neither National nor Labour suggesting a change in the company tax rate.
However, there would be complete divergence on individual income tax, he told the Otago Daily Times.
Labour and the Greens had signalled a wish to increase the top individual tax rate.
"This will be a major campaign platform for them. The key to making it palatable for their core voters will be the level at which the top tax rate kicks in to make sure it is only high-income earners who are paying the top tax rate."
It would be important for Labour to demonstrate the increased tax take would be directed to areas providing a tangible benefit, such as the proposal to provide up to three years’ free tertiary education, Mr Stevenson said.
National had signalled a preference to provide savings for lower to middle income earners rather than having high-income earners pay more, but only if it was affordable.
Debt reduction and infrastructure spending were seen as higher priority than tax cuts.
Deferring tax cuts while there were budget deficits was well understood by voters. It would be interesting to see if they remained as understanding when there were budget surpluses, he said.
It was "very unlikely" any of the main parties would advocate for a comprehensive capital gains tax, because it was politically unpalatable.
"Sweeteners get you elected. Brussels sprouts don’t, even if they are healthy."
Labour had signalled, if elected, it would form another tax working group to review the New Zealand tax system. Capital gains tax could be back on the agenda at that point, Mr Stevenson said.
Labour had also signalled it would like to simplify provisional tax but National had already introduced legislation to achieve that, so it was unlikely to be a major campaign point.Deloitte did not expect anything out of the ordinary from the major parties regarding tax, Mr Stevenson said.
The minor parties would have more scope to be innovative in their policies.
New Zealand First wanted to remove GST from food, to be funded by higher tax rates for high-income earners. Gareth Morgan’s wealth tax had also shown he was not afraid to think outside the square. If he continued in that vein, Mr Morgan would create debate, Mr Stevenson said.
Other minor parties’ announced tax policies were broadly in line with their general philosophies. Act New Zealand supported lower individual and company tax rates and the Greens proposed to exempt electric vehicles from fringe benefit tax.
"All parties will be wanting to support foreign-owned companies paying their ‘fair share’ of tax in New Zealand, as this is a very topical issue and is unlikely to alienate New Zealand voters."
Crowe Horwarth tax advisory managing partner Scott Mason said the year would be dominated by Inland Revenue’s business transformation and the operations of the key plank around business tax, withholding taxes and tax on investment income.
Base erosion/profit shifting (BEPS) protections would also feature strongly and the Employee Share Scheme review would happen.
"Legislation-wise, there will be a significant tax Bill introduced in March, dominated by the above, but probably only one in 2017 — compared to the normal two — due to the election.
"I think it is unlikely there will be substantial tax reform in a general sense in election year, but I would not be surprised to see some more tinkering in the social policy space."
One of the matters Crowe Horwarth was looking forward to was the resolving of challenges for getting IRD numbers for foreigners, as many property transactions were being affected by existing rules, Mr Mason said.
