Australian telco Optus has been told it will “suffer significant consequences” following last week's Triple Zero network outage.

During the network outage last Friday, four people died as around 600 customers were impacted.

Australia's federal government told the carrier it can expect major financial penalties.

The outage was caused after Optus carried out a network upgrade; however, within this process, a technical failure impacted Triple Zero calls.

Triple Zero (000) is Australia's main emergency service phone number.

Australia's communications minister Anika Wells said Optus “failed the Australian people," while Prime Minister Anthony Albanese said Optus’s behavior was “completely unacceptable."

The Guardian reports that the communications regulator wasn't informed of the outage by the telco until hours after it had been fixed. The regulator also noted that Optus provided “inaccurate” information.

“We will be considered about our response, but there will be consequences for [Optus] and the broader telecommunications sector. Optus will be held accountable for this failure. They and all providers have no excuses here,” said Wells.

“They must now work with the government and ACMA (Australian Communications and Media Authority) to make their systems better.”

Optus said that the outage affected a number of calls in South Australia, the Northern Territory, and Western Australia.

Processes weren't followed

The telco apologized for the outage in the immediate aftermath. In an update over the weekend, the carrier said that processes had not been correctly followed.

"Early investigations show that it appears that established processes were not followed," said Stephen Rue, CEO, Optus.

"In order to establish why this occurred, we are speaking with the individuals involved. As to the full technical detail of the network failure, we will need to leave that for the investigation."

Rue added that he has halted any further changes to the company's network systems until Optus establishes a "broader understanding of the events that have occurred."

"Further, our technical teams are monitoring Triple Zero call volumes and failure rates state by state 24 hours, seven days a week," he added.

In the company's update yesterday, Rue noted that two customers had contacted Optus' call center on Thursday morning to report that they could not contact Triple Zero, a day before the outage was reported.

"Our review of our call logs is continuing, and so far, as part of that process, they have found three further calls in relation to this. As we had not detected the Triple Zero failures in our network at the time of these calls, there were no red flags for the contact center to alert them to any live issues. This is not clearly good enough, and we are implementing a new compulsory escalation process following any customer reports of Triple Zero failures through our customer call center," added Rue.

It's not the first time Optus has suffered a significant outage that has impacted Triple Zero services.

Last year, the carrier was slapped with an AU$12 million (US$7.93m) fine for an outage in 2023. The outage, which happened on November 8, 2023, lasted more than 14 hours.

The fallout from the outage was so severe for Optus that its CEO at the time, Kelly Bayer, resigned. Its head of networks, Lambo Kanagaratnam, also quit months later.

DCD sends its sympathies to the family and friends of the deceased.