Researchers from the University of Adelaide and Flinders University spoke with people affected by the 2005 Eyre Peninsula bushfires, which took nine lives, destroyed 93 homes and blackened 80,000 hectares of land.

Almost 180 people were recruited for the initial study six months after the fires, with 103 and 87 completing the two-year and seven-year follow-ups.

It found that 13.4 per cent had PTSD six months after the bushfires, 10.7 per cent two years after, and 4.8 per cent after seven years.

Relocation was identified as a significant factor in predicting the onset of PTSD at both the six-month and two-year marks.

After seven years, personal loss, including the damage and destruction of property, was the key issue.

Associate Professor Venkatesan Thiruvenkatarajan said people forced to relocate after a bushfire should be carefully assessed and supported to reduce PTSD.

"These individuals need to be monitored over time and offered psychological support to prevent long-term psychopathology issues," he said.

"Those who suffer from personal loss also need to be monitored on a long-term basis and adequately supported to compensate for the loss of loved ones."

Assoc Prof Thiruvenkatarajan said implementing outreach programs where victims could have access to a general practitioner, psychiatrist or psychologist would be useful for their short-term mental health.

"Psychological issues after a natural disaster can be delayed or manifest into something more serious if not treated early," he said.

The bushfire victims were also asked about how close they were to the fire, whether they defended themselves and their homes, whether they were trapped or injured, and their emotional experience.

Lead author Richard Watts said the findings could hopefully lead to greater support for people who have lived through a bushfire.

The study has been published in the Australian Journal of Rural Health.

Australian Associated Press