Telstra and Optus delay 3G shutdown as concerns over emergency calls remain

Telstra and Optus have pushed back the closure of their 3G networks by two months, with the government welcoming the delay as it remains concerned over a "subset of 4G phones".

Telstra and Optus will now shut down their 3G networks from late October. Source: AAP / Bianca De Marchi

Australia's two largest telecommunications companies have announced they will delay the shutdown of their 3G networks.

Telstra and Optus confirmed the move on Wednesday morning, saying in a joint statement that they would use the extra time to communicate the upcoming closure to customers.

Telstra was set to shut down its 3G network at the end of August, and Optus throughout September.

But they now say this will happen from 28 October.

"We are joining with Telstra to launch a final public awareness campaign to really drive home the safety message and get the final groups of customers to act," said Optus' interim CEO, Michael Venter, in a statement.

Vodafone has already shut down its 3G network.

How to check if you're affected by the 3G shutdown

A Senate inquiry into the shutdown revealed thousands of handsets would not be able to make triple-zero calls.

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

There are also concerns that other devices including EFTPOS machines, medical alert devices, and fire alarms could also be affected by the shutdown.

"While I am pleased that customers and businesses now have additional time to prepare for the 3G switchover, I want to encourage all Australians to take action and check if their device could be impacted," Communications Minister Michelle Rowland said in a statement on Wednesday.

"The government remains concerned about a subset of 4G phones configured by the manufacturer to default to 3G for Triple Zero calls, and personal medical alarms that rely on the 3G network"

These 4G phones — 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.

Australians can text "3" to 3498 to check if they'll be impacted by the shutdown.

The Australian Mobile Telecommunications Association has also set up a website, which will tell you if you need to take action after entering your device's IMEI number.

Customers can also contact their carriers for further information, or visit them in-store.

With reporting by the Australian Associated Press.