A consumer group is warning some refurbished mobile phones from overseas suppliers will not work after the 3G network shutdown next week.
The switch-off impacts 3G devices, but the Australian Consumer Communications Action Network (ACCAN) said recent-model refurbished mobile phones of all brands purchased from overseas markets might also be affected.
CEO Carol Bennett said some internationally sourced phones from the US and China were not compatible with Optus and Telstra's main 4G frequency of 700 megahertz, or band 28.
Carol Bennett, CEO of ACCAN. (ABC News: Billy Cooper)
Ms Bennett said the chances of purchasing an internationally sourced phone from mainstream suppliers in Australia were slim, but people needed to remain vigilant when looking for a deal.
"These are phones that come from the US or China, [and] they may be newer models," she said.
"By checking before the closure, you will know whether your phone is going to work.
"You may that find that it's not going to work when you most need it … like to call triple-0 for instance."
How to check?
People can check to see if their device works by texting "3" to the number "3498".
Telcos have been preparing for a nationwide shut-off of the 3G network since 2019. Vodaphone closed its network in January.
"We're just saying to people please get on the front foot," Ms Bennett said.
"[The 3G shutdown] is really important for consumer access to functionality and greater speeds, greater data."
Another hit to cost of living
Queensland-based technology retailer Christoper Timms said the 3G shutdown would mean the low-cost phones used by his vulnerable customers would no longer work when the service ended on October 28.
Christopher "Timmsey" Timms says the 3G shut-off is unfair on those doing it tough. (ABC North Qld: Cameron Simmons)
Mr Timms said he began repairing old 3G phones around three years ago and selling them for about $30 as an affordable option for people needing a basic phone.
"Unfortunately, all those devices mainly ran off that 3G network," he said.
Mr Timms looked to source cheaper 4G models of phones, however the cost was too high for his business.
"The next cheapest phone available to them is about $180," he said.
"They just can't afford it."
Communications Minister Michelle Rowland says mobile phone suppliers must be transparent with customers. (ABC News: Adam Kennedy)
In a statement, Federal Communications Minister Michelle Rowland said Australian Consumer Law required technology retailers to be transparent with customers about the upcoming shutdown.
She urged Australians to check other devices such as medical alarms and smart watches that might rely on 3G.