A damning independent review has found Optus lost effective control of its network operations after outsourcing critical work offshore, contributing to the fatal Triple Zero failure that left hundreds unable to reach emergency services and has been linked to two deaths.

The review, led by former NBN Co director Kerry Schott, examined a September 18 network outage caused by a botched firewall upgrade.

It found at least 10 separate failures by Optus engineers and contractor Nokia during what should have been routine maintenance, ultimately blocking emergency calls for almost 14 hours.

According to the report, 605 people attempted to dial Triple Zero across South Australia, Western Australia, the Northern Territory and parts of NSW during the outage. Just 150 calls connected – a failure rate of around 75%.

Schott said the “real tragedy” was not just the initial technical error, but the prolonged failure to recognise and respond to warning signs.

“The necessary processes were in place, but their requirements were not performed properly,” she said.

A key finding was “very poor management” of Optus’s network operations, which were partially outsourced to Nokia in 2018, with much of the work shifted to India.

The review found morale at the offshore facility was low, checks were inadequate, alerts were given insufficient attention and staff were reluctant to challenge mistakes or escalate concerns.

The firewall upgrade was incorrectly classified as low-risk and urgent, allowing it to bypass senior review.

Crucially, the chosen procedure failed to divert call traffic before locking down network equipment, causing Triple Zero calls to fail even as regular voice calls rerouted successfully.

While stopping short of calling for CEO Stephen Rue’s (pictured) resignation, the review called for sweeping cultural and governance reforms.

The Optus board has accepted all 21 recommendations from the review, including overhauling risk management, improving emergency call testing and accelerating plans to bring network operations back onshore.

Optus will also expand its Australian call centres by around 300 staff to better support emergency and vulnerable customers.

Chairman John Arthur said the report is a “sobering read” and confirmed individuals would face consequences ranging from financial penalties to termination.