By Stephanie Gardiner

The shutdown of the 3G network has been delayed after Australia’s telcos came under fire over public safety risks.

Telstra and Optus jointly announced the companies would delay the 3G closure until October 28.

Both telcos had been preparing to switch off from the end of August, but a Senate inquiry revealed thousands of handsets would not be able to make triple-zero calls after the shutdown.

The inquiry was also told critical medial equipment, fire alarms, EFTPOS machines and waste and water infrastructure could be cut off in the shutdown.

A joint statement from Telstra and Optus on Wednesday morning said the companies would undertake a mass public awareness campaign to ensure all users were aware they needed to upgrade their devices.

The companies said it was critical customers checked their handsets were compatible with 4G and 5G and be aware if other devices, such as sensors and alarms, relied on 3G.

But the telcos’ executives both defended their actions in contacting customers in the years leading up to the end of 3G, which was flagged in 2019.

“We have been communicating to customers about the need to prepare and make the move for almost five years,” Telstra chief executive Vicki Brady said.

Optus interim chief executive Michael Venter said the telco had “pulled out all the stops” in contacting and supporting customers.

The federal government has been giving regular updates on the number of phones that will not connect to triple-zero after the closure.

There were still 77,000 affected handsets in early August.

These devices – often bought overseas or second-hand – use 4G data for regular calls and texts but bump triple-zero calls to 3G because they are not enabled with a technology called Voice over LTE.

Users might not realise their phone is configured this way by the manufacturer until the 3G network is switched off.

All telcos have a service for customers to check the status of their device by texting “3” to the number 3498.