Optus' head of networks, Lambo Kanagaratnam, has resigned months after the Australian telco suffered a lengthy outage.

Kanagaratnam left the company last week, becoming the second high-profile name at the company to depart after CEO Kelly Bayer resigned in November.

The outage, which happened on November 8, lasted for more than 14 hours and affected more than 10 million customers.

His departure was first reported by The Sydney Morning Herald, which stated that the company's interim CEO Michael Ventor informed staff at the telco via an internal memo.

Kanagaratnam served at Optus for nine years and had been managing director of networks since July 2023.

“After nearly nine years of service, Lambo Kanagaratnam has made the decision that the time is right for him to leave Optus. Lambo joined Optus in 2015 after an international career bringing a wealth of experience from working internationally in a number of countries around the world,” the memo reads.

“Lambo has helped our teams navigate through some uniquely challenging major natural disasters ranging from cyclones, floods, and fires as well as responding to the complexities that Covid and the recent outage presented for our customers and network teams."

Ventor added in the memo that Jorge Fernandes, group chief technology officer at Optus' parent company Singtel, will temporarily step into the vacant role until a replacement is found.

The outage caused transport delays and payment problems, and cut hospital phone lines.

The company said the outage occurred following changes to routing information from an international peering network after a routine software upgrade at 4:05 am the day of the outage.

However, a few days later this claim was disputed by Singtel, Optus' parent company.

During a Senate inquiry a couple of weeks after the outage, Kanagaratnam, along with Bayer, said that the telco operator was surprised at the scale and the size of the outage.

"We didn't have a plan in place for that specific scale of outage. I think it was unexpected," Kanagaratnam told the Senate. "We will take such exercises into consideration in the future."

Optus is still on the search for a new CEO. Bayer's tenure also saw Optus hit by a massive data hack in 2022.