Telstra has confirmed a "secondary issue" is continuing to affect some customers attempting to contact Triple Zero, even as the telco works to fully restore services following a major nationwide network outage driven by what it believes is a software defect. The company says it has reduced the frequency of Triple Zero call errors by approximately 90 per cent but warned some users may still be unable to reach emergency services.
The outage, which began disrupting services in the early hours of Wednesday morning with problems first being widely reported around 4:30am, left potentially millions of Australians unable to make phone calls or access the internet. Telstra said it had resolved the initial problem by 4pm on Wednesday, but the secondary issue affecting emergency calls persisted into Thursday.
What Caused the Telstra Outage?
Telstra's chief financial officer Michael Ackland said the root cause lay with malfunctioning "nodes" responsible for time synchronisation within network data centres in Sydney and Melbourne. These nodes keep time across Telstra's entire mobile network, meaning any disruption to them ripples throughout the whole system.
"You can imagine that lots of computer systems have to synchronise time," Ackland told reporters. "It's one of the ways that you authenticate what's going on in the network. And the time synchronisation in those nodes wasn't working as it should. We don't know why yet."
Telstra said it is confident it has identified and isolated a software defect linked to the failure, though investigations into the precise underlying cause remain ongoing. Ackland also confirmed there was no evidence of malicious activity behind the disruption — a point echoed by the Prime Minister, who sought to dampen speculation about a deliberate attack.
"Our investigation into the root cause is still underway, but we're confident we've identified a software defect and have been able to isolate it," the company said in a statement.
Triple Zero Calls and Hundreds of Welfare Checks
The impact on Triple Zero access proved more extensive than Telstra initially anticipated. The company revealed that by Wednesday afternoon it had conducted 395 welfare checks on customers whose emergency calls had failed or dropped out. Of those, 85 people were referred to emergency services for an additional welfare check or further assistance.
"The volume of welfare checks was higher than we expected, which prompted us to investigate further," Telstra said.
For customers still experiencing Triple Zero connection problems, Telstra advised that when a call fails, an error message will be received and the phone will automatically attempt to connect to an alternative mobile network. The company also encouraged users to restart their devices or try calling from a different phone if the issue persisted.
Emergency Management Minister Kristy McBain noted that Australian mobile phones are required to fall back to other networks when attempting to reach Triple Zero, providing a layer of backup for users caught in coverage gaps.
Communications Minister Anika Wells confirmed some Telstra customers were unable to reach Triple Zero during the outage but stressed the situation differed from past failures. "This is not a triple zero outage," she said. "This is a Telstra retail outage that has affected their customers right across the country." She also acknowledged the disruption to small businesses struggling with failed EFTPOS transactions as "incredibly frustrating."
Separately, a South Australian senator claimed on social media that she had received a report of someone losing their life because they were unable to call for help during the outage. Police disputed that claim.
Broader Disruption Across the Country
The scale of Wednesday's outage extended well beyond mobile phone services. The entire regional Victorian train network ground to a halt following the disruption, while regional and intercity trains in New South Wales also faced significant delays. Card payment systems were impacted across the country, adding to the pressure on businesses already dealing with connectivity failures.
Connection issues during the peak of the outage on Wednesday morning were concentrated largely in Australia's eastern states, according to outage-tracking data.
While Ackland suggested "tens of thousands" of customers may have been directly impacted, widespread online reports indicated the disruption could have been significantly larger. Telstra's own 2025 annual report states the company provides services to approximately 24.9 million retail customers nationally.
Telstra issued an apology to affected customers. "We know how much our customers rely on our network and understand just how much of a disruption this is to your day," the company said. "For that we're so sorry."
What Comes Next
Telstra says it is continuing to work to fully resolve the secondary issue and restore normal Triple Zero call reliability across its network. The company has also acknowledged that the incident exposed process failures that need to be addressed. "The fact that it occurred means that there is something in our process that we need to fix and to change — we are working through that," Ackland said.
For the latest on how this situation has developed, see our earlier coverage of Telstra's second Triple Zero fault emerging hours after the initial outage was resolved, as well as the growing calls for tougher telecommunications regulation in the wake of the outage.
