On 1 July 2018 Inland Revenue has updated an expenditure determination regarding people working in the screen production industry. If you are required to work away from home, the determination will apply to you.
The determination allows that from 1 July 2018, we are able to receive up to NZ$80 per day in per diem allowances.
Per diems are paid exclusive of GST, so when you prepare your GST invoice, you will need to calculate GST on the per diems received. So if a per diem is paid is $80 and the GST is $12 this will be included on their invoice as $80 + GST of $12 = total of $92. On the PAYE schedule the per diem is included but this is only at the $80. If a contractor is not GST registered, it is just the $80.
Read the full guidelines here