Mobile phone customers may not be able to use a different provider's network during widespread natural disasters.
Temporary disaster roaming would allow for mobile customers to switch networks in a disaster like a flood or bushfire, should telecommunications infrastructure be damaged.
While Telstra is testing how the technology could be used, the telco said it would most likely only be available across small geographic areas.
Telstra's manager of government relations Lisa McTiernan told a parliamentary inquiry into disaster resilience the roaming would not have worked during larger natural disasters, such as storms across Victoria that left thousands without power.
"The intent of temporary disaster roaming really is designed to address connectivity issues for smaller geographical locations ... it certainly isn't something that could be deployed or activated for a very significant event," she told the inquiry.
"What we don't want to occur is for a temporary disaster roaming activation to effectively be switched on and the remaining site gets completely inundated."
Similar data roaming capabilities are already in place in the US and Canada.
Head of regulatory at telco TPG Alexander Osborne told the inquiry that temporary disaster roaming would be costly to carry out in Australia, given shared data roaming between providers wasn't already in place.
"Disaster roaming is extremely limited in its use cases, it's a very expensive approach," he said.
"If you don't have domestic roaming arrangements in place beforehand, it's not going to work.
"If you had temporary disaster roaming, that's a panacea if you have a working site that's operational."
Earlier, the head of the Bureau of Meteorology told the inquiry people should not describe natural disasters as "one-in-100-year events" due to the term being misleading.
Chief executive Andrew Johnson said while the phrase was used to convey the severity of incidents like floods, it led to a false sense of security.
"Could this country please stop referring to weather events as one-in-100, one-in 1000, one-in-10,000? It confuses the community, it's very, very poorly understood," Dr Johnson told the inquiry.
"These are complex, statistical engineering constructs that mislead the community ... they're often used as a shorthand way of trying to communicate risk.
"They are technically very difficult for the average citizen to understand."
The head of the bureau said while the organisation had to walk a fine line with the levels of warnings to the public before natural disasters, Dr Johnson said the number of severe weather events would only increase.
"We have to get better as a nation. Everybody's involved in this situation, because it's not going to decrease, the risks and uncertainties are increasing in a changing climate," he said.
"We know that floods are going to happen more often, they're going to be large, we can do everything we can to provide as much advanced warning as possible."
Following severe flooding and storms in northern Australia, Dr Johnson said the bureau was undergoing "a lot of soul searching" on how the risk of weather events could be better communicated to the public.
