Australia's most vulnerable people are at greater risk of injury and death because community organisations cannot cope with extremes of weather, says the country's peak social services group.
The Australian Council of Social Service has found a poor level of preparation for extreme weather among community organisations, with the likelihood many would permanently collapse.
Such an outcome would leave society's most disadvantaged people, including the elderly, mentally ill and the homeless, ''at real and increased risk of death'', according to preliminary findings from the council's Climate Change and the Community Sector - Risks and Adaptations project.
Significant numbers of community groups ''are at risk of permanent closure'' if critical infrastructure were damaged, the report says. Such groups typically rely heavily on volunteers and provide a range of vital services, including support for young mothers, childcare, welfare and aged care.
Asked how long they would need to make alternative arrangements if buildings or premises became inaccessible, a quarter of the 600-plus respondents to the national survey said ''they would fail completely''.
A further 16 per cent said they would need at least a month to restart. Just one in nine said they could reopen within a day. The findings highlight susceptibility to extreme weather, which includes heatwaves.
Hobart smashed its highest temperature by a full degree on Friday, reaching 41.8 degrees, while the mercury hit 45 in Adelaide, its fourth highest since records began in 1887. More heat is on the way.
Episodes such as the current scorching heat add to the risks for people and organisations already struggling to cope, said Ross Womersley, executive director of South Australia's Council of Social Services, or SACOSS.
''People who are elderly are much likely to be vulnerable under these circumstances than younger, healthy adults,'' Mr Womersley said. Those living with disabilities, particularly if requiring highly modulated heat conditions, are especially exposed. Also easily forgotten during heatwaves are those with mental health issues.
Cassandra Goldie, chief executive of the Australian Council of Social Service, said the survey's findings were ''extremely important and deeply concerning''.
''We've got one in eight adults and one in six children living below the poverty line,'' she said.
''It's well understood that for those people, they are at extreme risk of being entrenched in their poverty situation once these sorts of events occur because any of the resources they have get wiped out.''
The project, which received federal funding from the National Climate Change Adaptation Research Facility, was to release its final report in March.
The council, though, is seeking approval to accelerate the disclosure to meet the January 18 deadline for submissions to a Senate inquiry on recent trends in and preparedness for extreme weather.