Png-NZ tax issues
The 183 rule does not apply till the second year onwards. The first year a non-resident is subject to a 325 day rule. Day counting means that any time spent on NZ soil even for only 5 minutes counts as a day.
I don't think however that there is a double take situation even for earnings in non-treaty countries. I believe that the IRD will allow a credit for tax paid and only impose a 'gap' tax on any amounts earned and taxed at a lesser percentage than NZ rates.I don't think that therefore any tax will accrue in NZ as PNG's rates are higher than NZ.
So maybe your residency is not important as it would be difficult to establish non-residency in NZ with what you are proposing.
If you receive any tax free allowances or non-taxed FBT benefits in PNG that would be taxable in NZ that may be a loss to you