Under NZ law, the IRD can tax your worldwide income. Unless there is a DTA with the other country. PNG does not appear to be on that list. Get yourself assessed as a non tax resident of NZ otherwise you could end up paying 2 lots of tax. Spend some time on the IRD website. Commuting is no worries, you're allowed up to 183 days in NZ each 12 months, just give them your permanent address as PNG. I own properties and have bank accounts and insurance policies etc in NZ (ie what I thought would be an enduring relationship) declared it all and was still declared a non resident for tax.
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Find out more
The Non-resident Contractors Team can help you with information about DTAs.
You can contact them at:
Non-resident Contractors Team
Inland Revenue
PO Box 2198
Wellington 6140
New Zealand
Phone 64 4 890 3056
Fax 64 4 890 4510
Email
[email protected]