Do the wealthy pay their fair share of tax?
Three recent reports have come to very different conclusions.
An Inland Revenue investigation has found New Zealand's wealthiest families pay less than half the amount of tax, across all forms of income, than most other New Zealanders.
But a different report by consulting firm Sapere Research finds the wealthy pay their fair share.
And a report from Treasury found that a third of all households receive more in tax credits and benefits than they pay in tax.
So why is it so hard to determine who's paying what? Robin Oliver is the former Deputy Commissioner of Policy at Inland Revenue.
He was previously on the United Nations Committee of Experts on International Cooperation in Tax Matters, and represented New Zealand on the OECD' Committee on Fiscal Affairs.
He now runs the tax consultancy OliverShaw - which commissioned the Sapere Report.