Optus is investigating its second significant outage in as many weeks, after an issue with a mobile phone tower on the New South Wales south coast led to nine failed emergency calls on the weekend.

The latest outage saw calls — including those to Triple Zero — affected for more than nine hours on Sunday in the Wollongong suburb of Dapto, the telecommunications giant said on Monday.

“We have investigated the impact of the issue on calls made between 3am and 12.20pm [on Sunday], including calls made to the Triple Zero network, and have confirmed with police, all callers who attempted to contact emergency services are OK,” Optus said in a statement.

“We sincerely apologise to any customers who were impacted.”

Among the callers was a person who needed an ambulance and had to use another phone to contact Triple Zero, as well as someone who could not get through and had no other phone available.

Two of the callers had accidentally called Triple Zero, Optus said.

An estimated 4,500 people were impacted by the Dapto outage before service to the area was restored, the company added.

Optus did not confirm exactly what had caused the fault.

The service interruption came just 10 days after a previous Optus outage led to hundreds of failed Triple Zero calls across South Australia, Western Australia, New South Wales, and the Northern Territory, and was blamed for at least four deaths.

Optus and the Australian Communications and Media Authority (ACMA) have launched investigations into that incident, which the telco said was caused by human error during a routine firewall update.


Optus says services in Dapto have been restored, but has not detailed the cause of the outage. Image: Optus

Finance Minister Katy Gallagher told ABC News on Monday that while the Dapto outage was “slightly different” to the one earlier in September, it was “still disappointing”.

“And although I understand Optus did make the necessary reports over the weekend, there's clearly more work to be done,” she said.

NBN outage impacts emergency calls in WA

A National Broadband Network (NBN) outage caused by a hardware fault in Western Australia’s south-east on Friday also affected local calls from NBN landlines, including to Triple Zero, police said.

The outage affected around 700 services in the the Goldfields-Esperance region between 11:30am and 10pm, in locations such as Bandy Creek, Castletown, Chadwick, Esperance, and West Beach.

Shadow Minister for Communications, Melissa McIntosh, told ABC News on Monday that the latest Optus and NBN outages highlighted why the coalition wanted an investigation “into the whole network, not just Optus”.

“People across Australia need to have confidence in our Triple Zero network — these are lives that are at risk, McIntosh said.

“… I believe it needs to be a thorough, independent investigation — and it’s not just into Optus; if NBN is also experiencing outages, it needs to be into the whole telecommunications network."

Telstra also suffered a mobile network outage in the WA suburb of Broadwater on Monday, which local police initially said could impact Triple Zero calls but was later found not to have impacted emergency calls.


The Liberal-National opposition is calling for an investigation into Australia's telecommunication systems. Image: Optus

Minister to meet Optus and Singtel over network issues

Communications Minister Anika Wells is expected to meet this week with senior representatives from Optus and its Singaporean parent company, Singtel.

Singtel Group CEO Yuen Kuan Moon apologised for Optus’s 18 September outage in a statement to ABC News last Wednesday.

"We are deeply sorry to learn about the network incident at our Optus subsidiary that has impacted triple zero calls, and to hear that customers could not connect to emergency services when they most needed them," he said.

"Our hearts go out to the families and friends of those who have passed away and we know that Optus will get to the bottom of this matter.

"We are working with the Optus board and management to ensure a thorough investigation of this incident to prevent any future recurrence."

Optus was fined $12 million in 2024 after its major outage in November 2023 prevented more than 2,000 people from calling emergency services.

UPDATE 30/09/25 11:25am: Communications Minister Anika Wells said on Tuesday she had met with Singtel CEO Yuen Kuan Moon and requested that Optus "employs external advisors to independently assess the company's network plans to provide confidence to the Australian Communications and Media Authority (ACMA) and the Australian Government that these problems will not reoccur".