As the 30th anniversary of Ash Wednesday and the 10th anniversary of the Canberra fires approach next year, Jim McLennan from La Trobe University's school of psychological science warned that such a system - while it had clear merits - could also lead some residents and visitors to bushfire areas to become lax.

''There's a real chance that some householders will pass over to agencies more and more responsibility for their own safety,'' said Dr McLennan, a project leader at the Bushfire Co-operative Research Centre. ''And we really don't want to see a situation of helpless passivity, in which householders do nothing until they're told.''

He said earlier versions of SMS alert systems under bushfire conditions had not worked reliably because networks were disrupted by fire or software glitches meant messages failed to reach the correct recipients.

''I don't think there has been a successful demonstration under real fire conditions of the system working well,'' he said.

Dr McLennan said social media were also increasingly becoming a source of information for people in disaster areas to share information.

He said this was evident last month as fires burnt near Port Lincoln in South Australia and during the Queensland floods.

However, he said, no one should rely on only one form of communication because fire could cause outages.

A national location-based SMS alert system came into effect this month, allowing Telstra customers to be contacted if they are in a disaster area. Customers with other carriers will join the system next year.

A spokeswoman for Bushfire Response Minister Peter Ryan said people should not rely solely on a text message; they should also get their information from a combination of methods, including the CFA website and ABC radio.