The Australian Communications and Media Authority (ACMA) filed court proceedings against Optus Mobile, a wholly owned subsidiary of Singtel, alleging 1005 breaches of the Telecommunications (Emergency Call Service) Determination 2019 all occurred on September 18, 2025 [1, 2].
The alleged breaches relate to failures during a network firewall upgrade on that date. The outage caused users to be unable to make emergency calls and has been linked to multiple deaths [1, 3]. ACMA says thousands of users were affected by the emergency call service disruptions [1, 3]. One source reports three deaths linked to the outages [1] while another cites four [3].
Following the outages, two senior Optus executives including the finance chief resigned [3]. Singtel shares rose 1.5% to SGD 4.68 after the lawsuit announcement [1, 2].
Optus said it would not comment further while court proceedings are ongoing. It added, “As the matter is now before the Australian courts, Optus will not be commenting further on these matters at this time. Optus is unable to determine the quantum of any potential penalties at this stage” [2]. The final fine will be decided by the Federal Court considering various factors, not solely based on the number of breaches [1, 2].
In 2024, Reuters reported that Singtel was in advanced talks with Brookfield Asset Management to sell a significant stake in Optus, though Singtel denied any imminent deal [3].
The ACMA legal action was filed on July 30, 2026, more than 10 months after the September 18, 2025 outage [1, 2]. Optus is reviewing the lawsuit and will respond in due course [1, 2].
