The ABN is the new identifier for dealings with the ATO and for future dealings with other governmental departments and agencies. This should eventually involve the replacement of group tax numbers and Australian Company Numbers [ACN] with a single number.
Applying for an ABN is not compulsory. However, an ABN is important even if the supplier is not registered for GST, otherwise ‘pay as you go withholding tax’ applies at the highest rate of 48.5%.
(The University's ABN is 65 542 596 200)
To check if an organisation has an ABN go to abr.business.gov.au