Optus executives could soon be forced to front a Senate inquiry to explain the company’s catastrophic Triple Zero outage which left hundreds of emergency calls unanswered across four states and has been linked to three deaths.

The Greens and Coalition senators are expected to unite to establish the inquiry when Parliament returns later this month, compelling Optus CEO Stephen Rue and senior executives to testify.

It follows revelations that the telco sent critical outage notifications to the wrong government email address and initially understated the scale of the disaster.

Greens senator Sarah Hanson-Young confirmed plans to move the motion, saying the inquiry would “get to the bottom of what went wrong at Optus, how regulators failed and how to prevent another deadly breakdown.”

Officials from the Department of Communications told a Senate estimates hearing this week that Optus’ September 18 outage notice went to an outdated email account, meaning the department did not learn of the incident until more than a day later.

The emails also incorrectly stated only ten Triple Zero calls had been impacted – a figure later revised to more than 600.

ACMA chair Nerida O’Loughlin told senators the regulator had found the initial Optus information “weird” and “clearly inaccurate.”

The watchdog has since launched its own investigation and warned Optus could face tougher penalties than the $12 million fine issued after its 2023 national outage.

Optus chief executive Stephen Rue (pictured above) has met with government and opposition MPs this week but is yet to face parliamentary questioning.

In a statement, an Optus spokeswoman said the company “will cooperate fully with any Senate inquiry” and pointed to an ongoing independent review led by former Sydney Water CEO Dr Kerry Schott.

The Albanese government on Wednesday blocked a Coalition move for a separate House inquiry, insisting its new legislation to strengthen oversight of the Triple Zero system will address the failures.

However, Hanson-Young said revelations of email mix-ups, delays and misleading reports “show how badly both Optus and the government dropped the ball.”