"Law enforcement" and national security is given as the verbatim headline justification when you reference Australia's Communication and Media Authority[] for rules on ID collection.

  Carriers and carriage service providers (CSPs) must help law enforcement and national security agencies.

  ...

  You must verify a customer's identity before you activate a prepaid mobile phone service. You can do this when the customer buys the service or when they try to activate it. The Determination on identity checks for prepaid mobiles lists the ways you can check a customer's identity.

[] https://www.acma.gov.au/support-law-enforcement-and-security...