The Australian government has been seeking answers about the disruptions at the country's No 2 telecom, which is owned by Singapore Telecommunications.
Singtel Group chief executive Yuen Kuan Moon plans to meet Australia's Communications Minister Anika Wells this week, a spokesperson for the minister's office said.
Yuen will meet Wells along with Optus chairman John Arthur and chief executive Stephen Rue, Singtel said.
"Singtel takes this matter seriously and will extend full co-operation to the Australian government and authorities to address the Optus issue," a spokesperson said.
Optus said on Monday that a faulty mobile phone tower site in Dapto, around 100km south of Sydney, interrupted services, including emergency calls, on Sunday morning and affected 4500 people.
"Optus continues to investigate the cause ... the issue has been restored," a spokesperson said by email.
The company said it "confirmed with police, all callers who attempted to contact emergency services are OK."
A network firewall upgrade triggered the 13-hour outage on September 18 that disrupted emergency call services in two states and the Northern Territory and potentially affected around 600 customers, some in remote areas who were unable to make calls, leading to the four deaths.
Anger over the outage has been growing in Australia, with Prime Minister Anthony Albanese calling it "completely unacceptable".
Rue has said checks suggested the first outage could have been caused by human error and admitted procedures were not followed during the outage.
An independent review has been set up and that is expected to be completed by year-end.
