The Australian Communications and Media Authority filed Federal Court proceedings against Optus Mobile on July 30, alleging 1,005 breaches of emergency-call rules during a September 18, 2025 network outage. The regulator, which oversees Australia's communications sector, says the carrier failed to give some callers access to the emergency service and failed to carry their calls to the required destination.

Triple Zero, written as 000, is Australia's main emergency telephone number. The lawsuit concerns access to that national service and does not allege that Optus's entire mobile network failed across Australia.

The court will decide liability and any penalty

The regulator is asking the court to declare that Optus Mobile contravened Australia's Telecommunications (Consumer Protection and Service Standards) Act 1999 by failing to meet sections 15 and 19 of the country's Telecommunications (Emergency Call Service) Determination 2019. It also wants the court to order financial penalties payable to the Australian government.

Each alleged contravention carries a maximum penalty of A$250,000. Applying that maximum to all 1,005 allegations produces a theoretical ceiling of A$251.25 million, but the court has not found Optus liable or imposed any penalty.

The theoretical ceiling is about US$177 million using the Reserve Bank of Australia's August 7 rate of US$0.7029 per Australian dollar. The conversion is approximate and does not represent a forecast of the court's eventual decision.

Firewall work cut off emergency calls for 14 hours

A December 2025 independent review commissioned by the Optus board found that network changes at 12:17 a.m. Australian Central Standard Time blocked emergency calls until service was restored at 2:34 p.m. The affected area covered South Australia, Western Australia and the Northern Territory, along with a small number of customers near the South Australian border in New South Wales.

The review counted 605 affected callers, some of whom tried more than once. Only 150 connected: 66 through another carrier and 84 through another Optus route. The remaining 455 callers, or 75 percent, did not connect.

The failure began during planned work on a management firewall at Optus's Regency Park exchange in South Australia. Engineers isolated equipment without first diverting traffic. Ordinary voice calls quickly found other routes, while most emergency calls did not complete the automatic transfer to an available network.

A judge's gavel resting beside legal books (illustrative image)
Australia's communications regulator has taken Optus Mobile to the Federal Court over alleged emergency-call failures. (Illustrative image; Photo by Tingey Injury Law Firm on Unsplash)

Warnings did not lead to a prompt response

The review identified at least 10 mistakes in planning and carrying out the firewall work. Nokia's network operations center used a procedure that omitted traffic diversion, and three peer reviews did not detect the missing step. Optus staff also failed to escalate doubts about the procedure before the change began.

Two network alerts did not prompt corrective action. Five customers later told the Optus call center that emergency calls were failing, but the cases were not escalated because the call center's process did not require it at the time. Optus recognized the wider problem only after South Australia's ambulance service contacted the company about 13 hours after the outage began.

The review said the duration increased the number of affected callers. It found that proper handling of the early alerts and checks could have reduced the outage to less than an hour, though that conclusion is the reviewer's assessment and not a finding by the Federal Court.

A previous outage brought an A$12 million penalty

Three Singtel Optus subsidiaries paid more than A$12 million in November 2024 after the regulator found emergency-call breaches during a nationwide outage one year earlier. The 2023 outage denied 2,145 people access to the emergency service, and Optus failed to complete 369 required welfare checks after service returned.

The regulator said the recurrence of a major emergency-call outage within two years contributed to its decision to go to court this time. That earlier payment does not establish liability in the new proceeding, which concerns a different outage and separate alleged contraventions.

Optus's response to the case remains unclear

The regulator said it would make no further comment while the case is before the court. APPI News could not find a public Optus response or defense filing for the new proceeding as of August 9, 2026.

The Optus-commissioned review predates the lawsuit and addresses the outage's causes and the company's response. Its factual account provides technical context, but the Federal Court will separately decide whether the conduct amounted to the 1,005 contraventions alleged by the regulator.

Frequently asked questions

What does Triple Zero mean?
Triple Zero, or 000, is Australia's main emergency number for police, fire and ambulance services.

How many callers failed to connect?
The Optus-commissioned review counted 605 affected callers. It found that 150 connected through Optus or another carrier, while 455 did not connect.

Why does the lawsuit list 1,005 alleged breaches?
The count concerns alleged contraventions of two legal duties across emergency-call attempts. It is not the number of unique callers affected by the outage.

Has Optus been ordered to pay A$251.25 million?
No. That figure is the arithmetic result of multiplying the maximum A$250,000 penalty by 1,005 allegations. The court has not decided liability or set a penalty.