The submission, made to the Parliamentary Joint Committee on Intelligence and Security review of the mandatory data retention regime that is part of the Telecommunications (Interception and Access) Act, also suggested that the period of data retention be extended beyond the current two years, though this point was not argued forcefully.
In arguing for retaining MAC addresses, the department submission said: "For example, including media access control (MAC) addresses and devices which identify serials would provide better information as to which device was being used at the time of an offence."
One case was cited as evidence for this: "In a recent case in Victoria, a mobile phone containing pictures of a terminally ill child was stolen at a shopping centre.
"Victoria Police were able to use the shopping centre’s security infrastructure to track MAC addresses in order to obtain surveillance footage of possible offenders. Charges have since been laid."
The department's argument for retaining IP addresses and port numbers was limited to one sentence: "Similarly, including IP addresses and port numbers to attribute data accessed on mobile phones, would allow agencies to make better use of mobile phone data."
While the department submission conceded that retaining the current period of data retention — two years — was "the most appropriate way forward", it also advanced several arguments about the use of older data in cases which it claimed backed its contention "that data held by commercial entities for longer periods can prove critical to prolonged investigations".
The demand for release of data fell after introduction of the law — in 2014-15 the number of requests was 363,336 and this dropped to 295.676 in the first full year of operation of the law — but the submission claimed "while the rate of use of telecommunications data has not significantly altered since the introduction of the Data Retention Act, the consistent volume of use demonstrates that this data remains a highly valued tool for law enforcement and intelligence agencies in their efforts to provide a safe and secure environment".
In 2017, the Australian Federal Police confessed to having illegally obtained the metadata of a journalist, due to what was put down to "just human error". The submission claimed the Commonwealth Ombudsman had found this was due to "a failure of administrative process and not an attempt to evade the oversight protections".
At the time, the then AFP chief Andrew Colvin told the media on a Friday afternoon that the officers were unaware that they needed to obtain a warrant to access the metadata of the journalist in question. The AFP informed the Ombudsman of the screw-up on the Wednesday of that week.
Regarding this, the submission said: "The timely and transparent investigation of this matter demonstrates that the considerations and oversight mechanisms governing the oversight of journalist information are effective."
The PJCIS has to submit its report on the review to Parliament by 13 April 2020.