Thousands of Samsung mobile phone users risk being out of pocket to replace devices that can't connect to triple-zero, after the federal government decided not to help.
Testing by Telstra found that more than 70 older model Samsung handsets weren't connecting correctly to the emergency number.
The telecommunications giant advised that 11 models will need to be completely replaced. The rest need immediate software updates to fix the problem.
Affected customers will be notified by email or text message about what to do next.
They have also been warned of their legal obligations, including that certain models must be replaced within 28 days or they will be blocked from the Telstra network.
Asked if there would be any government funding for people needing replacement phones, federal Emergency Management Minister Kristy McBain said responsibility lay with the companies.
"The telcos have contracts with customers and those customers ... pay for a service which includes a triple-zero service for their handsets," she told ABC radio on Friday.
"It's an issue that the telcos are going to have to address."
McBain said the government had been told up to 10,000 devices might be affected.
Free replacements to be offered, but not for everyone
Some of the affected users will get free handsets, but telcos and Samsung have stopped short of offering blanket replacements.
"If a replacement is required, we'll provide some options based on our customer's needs," a Telstra spokesperson said.
"We are providing some customers in vulnerable circumstances with access to a free replacement. Other customers will be offered an affordable alternative."
A Samsung spokeswoman said the company was available to answer questions and will "provide an offer to customers who require their devices to be replaced".
An Optus spokesperson urged clients to contact its customer service team and pointed affected users to Samsung for options.
McBain also flagged that Optus will be facing fines following the completion of an investigation by the Australian Communications and Media Authority (ACMA).
Greens communications spokeswoman Sarah Hanson-Young said Optus needed a cultural overhaul and accused it of putting "profits ahead of safety".
"You wouldn't want to see this exodus of executives as just rats jumping ship, and this company has a problem with its safety record," she told ABC radio.
"It has a problem with how it deals with its customers, and it's time that we review its licence."
The Greens have been pushing for a Senate inquiry to be held before Christmas.
Hanson-Young is confident the inquiry will get the necessary support when parliament returns next week.
In a statement on Friday, ACMA said it had rejected a proposed telecommunications industry code, deciding it would not provide appropriate community safeguards.
"Australian consumers need to be confident that they will be treated fairly when purchasing services, have protection from irresponsible selling, are provided clear and relevant information on mobile coverage and that they will not be unfairly disconnected," acting chair Adam Suckling said.
"In our view, the draft code would not deliver the level of protection the community should expect."
Suckling said it was disappointing the telcos had not been able to develop a proposal that would "deliver what their customers deserve" despite extensive feedback.
