Optus boss Kelly Bayer Rosmarin has resigned after the telecommunications giant suffered a fraught 18 months marked by a cyberattack and an hours-long outage that affected millions of Australians.

Bayer Rosmarin tendered her resignation on Monday morning after facing a Senate grilling on Friday.

“It’s been an honour and privilege to lead the team at Optus and to serve our customers,” she said.

“I was also able to communicate Optus’ commitment to restore trust and continue to serve customers.

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

Chief financial officer Michael Venter will take over as interim CEO while continuing in his current position.

Former Optus business managing director Peter Kaliaropoulos will become the company’s chief operating officer from Wednesday, a newly created position reporting to Venter.

-more to come

-AAP