But the findings haven’t been publicly released, beyond the government saying it makes recommendations “aimed at ensuring the telco industry learns from this outage”.
“We will consider the recommendations from the review, and publicly release both the final report and the government’s response in due course,” Communications Minister Michelle Rowland said in a statement on Friday.
The Optus outage in November left more than 10 million customers without phone and internet access for up to 14 hours and sparked hundred of complaints to the industry watchdog.
In February, the Telecommunications Industry Ombudsman reported it had received more than 900 complaints about the incident.
Twenty per cent of those complaints were from small businesses.
Complaints included financial losses, termination fees and a lack of, or delayed action, by the telco giant.
In terms of reparations, most customers sought credits, refunded or discounted services, financial compensation or an apology.
“For some people, the offer of free data to compensate for a full day outage is fair and reasonable,” ombudsman Cynthia Gebert said at the time.
“But businesses who lost profit, people who couldn’t call triple zero, or who experienced other significant losses told us that free data is not enough.”
The broader review, led by former deputy chair of the Australian Communications and Media Authority, Richard Bean, examined emergency call arrangements, customer communications and complaints handling following the outage.
“While the technical cause of the outage was not within scope of the review, the government understands that the disruption to some Triple Zero calls was predominantly caused by a failure of Optus 3G towers to wilt,” the communications department said.
Wilting is an industry practice where signals from mobile towers are powered down during disruptions to allow Triple Zero to be carried by another network.
“We want industry and government to learn the lessons from this event, and take steps to prevent this type of disruption occurring again,” Ms Rowland said.