Police are investigating a death potentially linked to a catastrophic Telstra outage that blocked more than 600 Triple Zero calls, as the telco admits the network failure was twice as bad as initially claimed and triggered a second major fault.

Officers said on Thursday afternoon they were investigating the death of a person at a regional hospital in South Australia on Wednesday, after being directed to the family through the office of Liberal senator Kerrynne Liddle, who had publicised concerns about the Triple Zero outage.

The admission that the outage stopped about twice as many emergency calls as first acknowledged by the nation’s largest telecommunications company came as federal data showed there were still 126 welfare checks that authorities had not yet resolved on Thursday afternoon.

Communications Minister Anika Wells rounded on Telstra, demanding “total transparency” over the outage after the company took hours to inform her office that it had begun.

“Telcos should act as soon as they become aware of something they need to tell the public about,” she said in a statement. “What Telstra knew, when they knew it and how they communicated it to stakeholders will be the subject of investigation.”

On Thursday afternoon, Telstra’s chief financial officer Michael Ackland – who has been managing the crisis while the company’s boss, Vicki Brady, returns from holidays overseas – said for the second time that the outage was over.

He defended the time Telstra took to inform Wells, whose office was told of the first outage around 7am on Wednesday. Customer reports suggest it began around 3am, and Telstra has said it became aware by about 4.30am.

“We will always communicate with customers first when we see that there is an issue and there are certain thresholds as to … when our obligations are to communicate with everyone,” Ackland said. “As soon as the incident reached that threshold, we communicated within minutes to the minister.”

Ackland told a Melbourne press conference that 639 welfare checks had been made since the outage began, with 170 cases passed to police and seven people telling the company they needed help.

The Telstra executive confirmed reporting by this masthead that a glitch had reset crucial timing systems to November 2006, causing parts of the network to reject customers’ phones showing the correct time. “There was a glitch in the software that reset the GPS timer,” he said. “It was a software glitch that caused the time to click back.”

Telstra has kicked off an internal analysis of the outages while the communications regulator, ACMA, has already commenced its own probe on behalf of the government.

The second fault emerged on Wednesday night, hours after Telstra had declared its network was operational at about 5.15pm. Ackland said it stemmed from the same software defect as the first fault but had to be fixed in a different way.

The disruption dragged into a second day for commuters. Victoria’s entire regional train network remained suspended through Thursday’s morning peak and some trains in the NSW Hunter and Southern Highlands were also affected, though the nation’s rail began returning to normal throughout the day.

One woman, identified only as Lynne, told the ABC on Thursday morning that her 95-year-old mother collapsed at her home in the Hunter region of NSW and could not use her personal wearable alarm to get help because of the outage.

“She was pressing her … alarm to get help and without Telstra or without it piggybacking to another provider to carry that emergency through, it could have been life and death for her,” said Lynne, who ultimately found her mother distressed but unharmed. This masthead has not independently verified that account.

Two internal Telstra sources had attributed the outage to the timekeeping fault before Telstra confirmed it. Modern mobile networks rely on precise timing to authenticate devices, and the incorrect date caused parts of the network to reject customers’ phones. Ackland said a full root-cause analysis would begin immediately, and rejected suggestions the network was fragile, calling it “a complex system” with built-in redundancy.

Questions grew over how quickly Telstra told the government. Earlier on Thursday, Wells said on the ABC’s AM she “would have liked to have heard earlier” and that the apparent delay would form part of the investigation, but declined to call for immediate resignations.

“The Triple Zero Custodian advised me that state and territory emergency authorities have not yet reported any adverse outcome caused by Telstra’s outage, with 44 welfare checks affirmatively cleared, out of 170 referred,” she said in a subsequent statement.

Liddle said on Wednesday that her office had received a report of a death following an apparent failure to reach Triple Zero during the outage. South Australia Police initially said they were not aware of any death as a result of the outage.

On Thursday afternoon, police said they had since made contact with the family of a person who died at a regional hospital on Wednesday, and had opened an investigation into the cause and circumstances of the death. They will prepare a report for the coroner. Police suggested Liddle’s office had initially been un-cooperative, while Liddle had said she had wanted to leave it to the grieving family to decide whether to inform authorities.

“I prioritised the privacy of the family during this time,” Liddle said on social media. Telstra’s outage, she declared, was “completely unacceptable.”

Telstra was fined more than $3 million in 2024 over an earlier outage that stopped some customers reaching Triple Zero. The telco is now facing potential penalties in the tens of millions of dollars.

Australia’s telcos have been under sustained scrutiny over reliability since two Optus failures. A nationwide Optus outage in November 2023 knocked out more than 10 million services and left about 2000 people unable to reach Triple Zero, and a separate Optus outage in September last year, in which hundreds could not reach the emergency line, was linked to two deaths and led to powers for a Triple Zero Custodian and tougher rules now being tested by Wednesday’s failures.

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David Swan is the technology editor for The Age and The Sydney Morning Herald. He was previously technology editor for The Australian newspaper.Connect via X or email.