Telstra has confirmed that a "secondary issue" is continuing to affect some customers trying to reach Triple Zero, even after the telecommunications giant largely resolved the major nationwide outage that crippled phone and internet services for potentially millions of Australians on Wednesday. The company says the frequency of the error has been reduced by approximately 90 per cent, but warned some users may still be unable to connect to emergency services.
The outage, which began disrupting services from around 4:30am on Wednesday, June 8, left customers across the country unable to make calls or access mobile data, with connection problems concentrated in Australia's eastern states during the peak of the disruption at around 10am. Telstra said its network had been largely restored by 4pm on Wednesday, but the secondary problem affecting emergency calls persisted into the evening and beyond.
Software Defect and Timekeeping Nodes Identified as Root Cause
Telstra's chief financial officer Michael Ackland told reporters the company was confident it had identified and isolated a software defect responsible for the disruption, though a full investigation into why it occurred remains ongoing.
Ackland pointed to malfunctioning "nodes" in data centres in Sydney and Melbourne that manage time synchronisation across the mobile network as the likely trigger for the initial outage. Because these nodes keep time across Telstra's entire mobile infrastructure, any failure in that system cascades throughout the network.
"Time synchronisation in those nodes wasn't working as it should. We don't know why," Ackland said, adding there was no evidence of malicious activity behind the failure.
"You can imagine that lots of computer systems have to synchronise time — it's one of the ways that you authenticate what's going on in the network," he said.
In a statement, Telstra said: "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."
For more on how the outage unfolded and its initial impact on emergency services, see our earlier coverage of the Telstra outage Triple Zero crisis and welfare checks.
Hundreds of Welfare Checks Conducted as Triple Zero Failures Mount
The scale of the Triple Zero disruption proved larger than Telstra initially anticipated. By 5:30pm on Wednesday, the company had conducted 395 welfare checks on customers whose emergency calls had either failed to connect or dropped out after connecting. Of those, 85 people were referred to emergency services for further assistance or an additional welfare check.
"The volume of welfare checks was higher than we expected, which prompted us to investigate further," Telstra said in a statement.
The company advised customers experiencing Triple Zero connection errors that their phone would automatically attempt to connect to an alternative mobile network, as required under Australian telecommunications regulations. Customers were also encouraged to try restarting their device or using a different phone if problems persisted.
"In these cases, when you call Triple Zero you will receive an error message, and your phone will try to connect to an alternative mobile network," Telstra said. "As part of our backup process, we will complete a welfare check where we detect a failed Triple Zero call."
A South Australian Liberal senator posted on social media claiming she had received a report that an elderly person had died after being unable to reach emergency services during the outage. However, police disputed that claim.
Ministers Respond as Broader Disruptions Felt Across the Country
Communications Minister Anika Wells confirmed that some Telstra customers had been unable to contact Triple Zero during the outage, while stressing the situation differed from previous emergencies involving emergency call failures.
"This is not a triple zero outage," Wells said. "This is a Telstra retail outage that has affected their customers right across the country."
Emergency Management Minister Kristy McBain reminded the public that Australian mobile phones are required to fall back to other networks when attempting Triple Zero calls, providing an additional layer of protection.
The outage had a wide ripple effect beyond phone and internet services. The entire regional Victorian train network was brought to a halt, and some regional and intercity train services in New South Wales experienced significant delays. EFTPOS and card payment systems were also disrupted across the country, with Wells acknowledging the impact on small businesses as "incredibly frustrating."
Ackland suggested as many as "tens of thousands" of customers could have been directly affected, though online reports indicated the true figure may have been considerably higher. In its most recent annual report, Telstra noted it provides services to approximately 24.9 million retail customers nationally.
What Comes Next for Telstra Customers
Telstra said work to fully resolve the secondary issue and restore normal Triple Zero call reliability across its network was continuing. The company also acknowledged it needed to examine the processes that allowed the fault to occur in the first place.
"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.
Telstra apologised to customers, stating: "We know how much our customers rely on our network and understand just how much of a disruption this is to your day. For that we're so sorry."
For a full timeline of events and the second fault that emerged after the outage was declared resolved, read our report on Telstra's second Triple Zero fault hours after the major outage was declared fixed.
