Emergency line to be reinforced against future outages

Australia's triple zero line will be better protected against future technical issues, as Optus apologises again after an outage left thousands of Australians unable to contact the crucial service.

Nearly one in three Australians were left without phone and internet services when the telco company experienced a nationwide outage in November.

During the 14-hour event, thousands of emergency calls made to the emergency line triple zero were also unable to go through, putting lives at risk.

Communications Minister Michelle Rowland has announced the federal government has received a review into the crippling outage and will begin implementing changes over the next 12 to 18 months to improve accountability of telecommunication giants and boost oversight of the emergency network.

"This is the single biggest review of the triple zeros service in over a decade," she told Sky News on Tuesday.

"Whilst in unfortunate circumstances with so many tens of millions of customers were impacted - businesses and consumers alike - it has given important guidance for lessons for the future and things that need to be done to really lift the performance a triple zero."

In accordance with the recommendations, the government will introduce rules mandating how, what and when telcos communicate with customers during and after a major outage.

A testing regime will also be set up to ensure the emergency hotline remains accessible.

The review also recommended carriers conduct testing every six months to ensure sustained access to the emergency network.

The industry will need to give the regulator a work plan after a major outage that explains how an impacted company will work to prevent one in the future.

Triple zero legislation and regulation will also be reviewed.

"It is certainly a feat of engineering that - irrespective of where you are in Australia - people are able to get access to police ambulance or fire when they dial triple zero," Ms Rowland said.

"But at the same time this ecosystem takes a lot of factors to work in it and part of (the review's) criticism was everyone was doing their part but they stayed in their lanes and didn't think about how this worked across the system."

The main cause of the triple zero issues during the outage was due to a lack of "wilting" on Optus's 3G network, which is supposed to power down dysfunctional towers so calls could be carried by another tower.

According to Optus, the issue has now been addressed but Ms Rowland maintains it highlighted vulnerabilities in the system that the government will address by implementing all 18 recommendations in the review.

Optus's interim CEO Michael Venter confirmed he has received the review and assured customers changes had already been made.

"We would like to apologise again to all our customers who were affected by the outage," he said in a statement.

"(We) acknowledge the importance of having an emergency services system that prioritises public safety."