Tens of thousands of older mobile phones and other devices will stop working from Monday when the nation’s 3G network is shut down.

Australians are being urged to help older family members or neighbors check the devices amid concerns people are losing access to triple-zero services and medical monitoring equipment.

When will Australia’s 3G network be switched off?

Telstra and Optus will shut down their 3G coverage from Monday, affecting mobile phones, tablets and medical devices still using the older network.

The telcos had planned to begin shutting down their 3G network earlier this year, but concerns about the hundreds of thousands of users still on the network led both to delay the switch.

Which devices will be affected by the 3G shutdown?

As of last week, there were 18,000 3G mobiles and 70,000 4G Telstra non-VoLTE mobiles, both using 3G for calls, representing 0.3% of the company’s mobiles.

Another 58,000 4G VoLTE phones using 3G for triple zero calls will be blocked when the network is down as a safety measure. These phones are older devices, often purchased overseas.

Telstra and Optus users can text ‘3’ to 3498 to see if their handset will be affected. Affected Telstra customers heard a pre-recorded message before calls were made, and both telcos sent warning text messages and emails.

Federal Communications Minister Michelle Rowland urged people to “check the technology now”.