Should you backdate a GST registration?
When MUST you backdate a registration?
A business making taxable supplies must register for GST when they pass the $75,000 turnover threshold.
This can and does get missed from time to time.
The system does allow a registration to be backdated for up to 4 years. (It can go further if fraud is proved).
If your client has crossed the threshold and should register then you must. If they passed this threshold a year ago you should backdate the registration and change the accounting to include the GST impact.
Backdated registrations mean 1/11th of the taxable supplies is treated as GST collected so you have a payment to make.