Are you referring to adding an employee in QuickBooks Online (QBO)? If so, the option of adding an employee outside Australia (AU) is unavailable because the system needs a residential suburb of an employee. QBO will determine the tax scale from the information you've entered.
I recommend contacting our Payroll Support. They have more tools to give you further workarounds.
Here's how to get in contact with them:
In your QuickBooks Online, click the Help menu in the upper-right corner.
On the Search tab, click an article and select Contact us at the bottom. Then, enter the details of your concern.
Choose how you would like to connect with them: either via Callback or Chat.