Yes, Australia Toll free, DID and National numbers have been portable since 2000 and are regulated by the  Australian Communications and Media Authority (ACMA).

Starting the Number Porting Process

• Contact your Account Manager or email your request to sales@avoxi.com 
• You will then receive a  Letter of Authorization required to port your numbers to AVOXI's network. 
• In most countries we require the below-supporting documents: 
  • Full registered Company name
  • Numbers you wish to port
  • The billing information your existing carrier If you are unsure of the exact billing information your current carrier has on file, there is a simple solution. Simply request a record of service from your provider.