CEO Rosmarin said it was an “appropriate time to step down” following the outage which left millions offline and unable to make calls or send texts.

South Australian Government bodies including SA Health were also caught up in the outage, as were Service SA and SA Water. 

The Singapore-based parent company of Optus, Singtel, today announced Rosmarin would be replaced by the current chief financial officer Michael Venter on an interim basis while it searches for a new CEO.

Venter joined Optus as CFO in 2021, and today said he recognised “the need for Optus to regain customer trust and confidence”.

Rosmarin said it was an honour to serve as Optus CEO.

“On Friday I had the opportunity to appear before the Senate to expand on the cause of the network outage and how Optus recovered and responded,” she said.

“Having now had some time for personal reflection, I have come to the decision that my resignation is in the best interest of Optus moving forward.

“It’s been an honour and privilege to lead the team at Optus and to serve our customers. I am proud of the team’s many achievements and grateful for the support of the Optus team.”

Singtel CEO Yuen Moon said Rosmarin “led with integrity”.

“Optus appointed Kelly at the beginning of the pandemic, and we acknowledge her leadership, commitment and hard work throughout what has been a challenging period and thank her for dedication and service to Optus,” Moon said.

“Kelly has always led with integrity and had all stakeholders’ best interests at heart.

“We understand her decision and wish her the very best in her future endeavours.”

The new CEO will take on the challenge of regaining “customer trust and confidence” according to Moon.

“We recognise the need for Optus to regain customer trust and confidence as the team works through the impact and consequences of the recent outage and continues to improve,” Moon said.

“Optus’ priority is about setting on a path of renewal for the benefit of the community and customers.”

In addition to Venter’s interim appointment, Singtel has announced former Optus Business managing director Peter Kaliaropoulos will rejoin Optus as chief operating officer.

“Optus is an integral part of our group’s business,” Moon said.

“We view the events in recent weeks very seriously. We fully recognise the importance of Optus’ role in providing connectivity services to the community and the importance of network resiliency and security.

“That is a top priority in all markets where our companies operate in. I have every confidence our Optus team will exert all efforts to deliver customers and regain their trust and confidence.”

Following the outage, Optus announced it would give customers free data. Eligible postpaid customers will be able to access 200GB of extra data, while prepaid customers will receive unlimited data on weekends until the end of the year.

Small businesses disrupted after the 12-hour outage ground trading to a halt will also be able to take advantage of the deal.