1. NZ taxes residents on their worldwide income irrespective of the source of that income
2. Taxes non-residents only on that income which has its source in NZ
s BD 1(4) and BD 1(5)
Income from land owned & Income from use in NZ of personal property
are treated as having NZ source
As a general rule, the Inland Revenue Department can reassess you for up to 4 years, however, if they believe that your tax return is fraudulent, or misleading, or it has left out income, you can be reassessed at any time and there is no limit to how far back the IRD can go. Similar rules apply to GST.