Who says anything about crime? the goal is just so they can associate phone numbers with id cards in some fashion right?
If they want to know what tourists are posting about their country that's good enough.
"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.
Unfortunately I can't dig up the original debate from 1997 on the Telecommunications Act when the requirement appears to have been introduced. Would be shocked if it did not include similar language from the representatives shilling the requirement, though.[] https://www.acma.gov.au/support-law-enforcement-and-security...
Like so many laws, nothing to do with stopping crime, but an obvious push to strip the populace of its rights.