The start date of a GST registration is usually the date the application is made.
In exceptional circumstances we can backdate your GST registration start date. Backdated registrations must be supported with relevant documents, such as bank statements, tax invoices issued, and copies of any contracts. You’ll also need to provide a detailed explanation of your taxable activity and why the registration was not filed sooner.
At the time of registering you can send us a message in myIR and attach supporting documents.
You can apply for an IRD number and register for GST when you register a company online with the Companies Office.