FIRE services are testing an emergency warning system that could work in high-risk bushfire areas that are also mobile phone black spots, such as Victoria's alpine region and the Dandenongs.
But the radio-based technology cannot be used until broadcasters allow warnings to interrupt their transmissions, and the federal government alters communication laws.
Firefighters brace for more dangerous weather
NSW firefighters are bracing for more dangerous weather as they battle to contain the blaze that has already destroyed more than 30 houses.
As Victoria braces for another day of total fire bans on Thursday, emergency services have pleaded with residents in high-risk areas to take responsibility for their own safety and not wait until they are warned to leave if they fear they are under threat of bushfire.
Residents who had to flee their homes during fires near Ballarat last week complained that SMS warnings were inadequate, with some not receiving messages at all. That prompted Emergency Services Minister Peter Ryan to say they should not rely on the system.
Last June, Mr Ryan urged the Gillard government to upgrade telecommunication services to ensure Victorians were warned of disasters. He said his office had received complaints about black spots in about half-a-dozen areas, including the alpine region and Traralgon South.
The system, which would provide warnings over the radio similar to those issued to drivers in the Burnley and Domain tunnels, was tested in November at Eldorado, in north-east Victoria.
Fire Services Commissioner Craig Lapsley requested the trial. A spokeswoman said initial feedback showed the system could benefit some high-risk bushfire areas with limited mobile phone reception, but results would not be finalised until the end of the fire season.
The results will be provided to Victoria's emergency services to consider.
''Further testing is required to understand the limitations of the technology in emergency situations, the potential impact on all broadcasters and the community, and any requirements of the Australian Communications and Media Authority (ACMA),'' she said.
The office of federal Communications Minister Stephen Conroy has been briefed about the active frequency override technology, which has been developed by a Victorian company, Emergency Warning Systems. Its managing director, Geoff Drucker, said a transmission unit that could work over a radius of 40 kilometres would cost about $50,000, less if multiple units were commissioned.
A smaller unit, which could be installed in emergency vehicles and would have a range of about two kilometres, would cost about $7500.
A government spokeswoman said legislative change would be needed to allow the system to override public and commercial broadcasters, but emergency services would have to commit to using the technology before any changes were made. ACMA had been consulted about the system.