by Michael I. Atlas, CA on Thu Mar 11, 2010 4:00 pm
Firstly, you might want to look into whether you really need to withhold NZ tax from the employees pay, given that the work would be done outside of NZ.
In any event, the way that double tax would be avoided would be the opposite of what you are suggesting. Namely, NZ should give a foreign tax credit for the Canadian tax payable.
Canada would never give a foreign tax credit for the NZ tax, because a foreign tax credit only applies to foreign source income. In this case, the "source" of the income would be considered Canadian, since the employment duties are performed in Canada, so there would be no basis for claiming a foreign tax credit in Canada.
On the other hand, from the NZ perspective, it should be viewed as foreign source income, and assuming the salary is taxed at all in NZ, they should allow a foreign tax credit for Canadian tax.
The reporting and claiming would be done by the employee on his/her tax return.
The same would be true in the situation you describe regarding the US. They are not going to give a foreign tax credit for NZ tax on US source income.
The relief is foreign tax credit claim in the country of residence by the employee.