The Optus company sign and logo is displayed in a store window in the central business district in Sydney, Australia, on Sept. 23, 2025. Lisa Maree Williams/Getty Images
Optus has pointed to its technology partner Ericsson as the source of a mobile tower malfunction in Dapto, New South Wales, that left calls unable to connect, including 12 attempts to Triple Zero.
The Sept. 28 outage, which impacted around 4,500 residents, occurred when 4G services on a single tower failed to operate even though the tower appeared active on the network.
As Optus’ 5G network does not yet carry voice services in Australia, calls could not be placed or redirected.
In a statement, Optus said the tower outage was tied to a failure in the Ericsson equipment.
“Our ability to detect the outage was impacted as the Ericsson equipment in the cell tower did not alarm that 4G services were not operational,” the company said.
At Optus’ request, Ericsson carried out a health review of its network elements and concluded the Dapto fault was “an anomaly they have not seen elsewhere.”
The company has now escalated the problem to its global Product Development Unit for urgent analysis.
Ericsson provides much of the radio technology underpinning Optus towers and core infrastructure.
The Dapto incident affected one tower out of more than 9,000 nationwide. Optus confirmed that one emergency call attempt failed during the disruption, though the individual was able to reach Triple Zero from another phone.
The telco stressed the issue was unrelated to the Sept. 18 nationwide outage caused by a firewall upgrade, which blocked 600 Triple Zero calls and has been linked to three deaths.
Government Demands Accountability
The revelation adds fresh pressure on Optus as Communications Minister Anika Wells calls for the company to restore public trust. Wells has ordered Optus to appoint an independent external reviewer to oversee its response.
“This is for Optus to take accountability for,” Wells said after a meeting with Optus Chief Executive Stephen Rue and Singtel boss Yuen Kuan Moon.
“There is a very serious lack of confidence in Optus to deliver Triple Zero services.”
She confirmed the Australian Communications and Media Authority (ACMA) is running a formal investigation into both the Dapto failure and the earlier nationwide collapse.
The two incidents, less than two weeks apart, have increased scrutiny of Optus’ governance and prompted wider questions about whether systemic underinvestment left the carrier exposed.
Yuen apologised to the families affected by the Sept. 18 failure and said it had been caused by a “step being missed by someone at Optus” rather than systemic underinvestment.
“Our hearts go out to the family and friends of the people who passed away,” he said.
He described the breakdown as a “process issue,” separate from the Dapto outage.
