If your business circumstances change, you may not need to be registered for GST anymore. For example:

  • selling or closing business (you need to cancel your GST registration within 21 days of the sale or closure)
  • business turnover drops below the compulsory threshold, unless you’re a taxi driver
  • change of business structure, for example from a sole trader to a company

Cancelling your GST registration can save you time and effort because some other registrations automatically cancel at the same time, including:

  • luxury car tax (LCT)
  • wine equalisation tax (WET)
  • fuel tax credits (FTC)

Before cancelling your GST registration, make sure you check you’ve finalised all of your tax obligations.

 

Information from : https://www.ato.gov.au/Newsroom/smallbusiness/GST-and-excise/Do-you-still-need-to-be-registered-for-GST-/