A study of almost 1000 women from the ACT and south-eastern NSW who reported exposure to the Black Summer fires found they had higher rates of depression and anxiety.

The women had depression scores 12 per cent higher than established Australian norms, anxiety scores 35 per cent higher, and stress scores 43 per cent higher.

"Women with greater exposure to bushfires/smoke but not COVID-19 had poorer scores on all mental health measures," the study found.

The results were drawn from a study of mothers who gave birth between November 1, 2019 and December 31, 2020.

The study found women who reported high exposure to bushfires had a more than four-fold higher risk of having moderate to severe depression and anxiety.

But the authors were surprised the same was not true of bushfire smoke exposure.

"It is possible that the effects and media coverage of the most acute bushfire exposures involving more direct threat to individuals, their families, and their possessions might have distracted from longer-term concerns relating to smoke exposure," the paper said.

"Alternatively, as a large proportion of women were exposed to smoke, albeit at different levels and for different durations, it is possible that even low or brief smoke exposure led to relatively similar concerns.

"If this were the case, then the lack of significant effects for smoke exposure might reflect widespread rather than non-existent concern."

The paper said it was "somewhat surprising" women with a past history of either depression, anxiety, or both, were not predisposed to being more adversely affected by bushfire exposure.

"In addition, there was no evidence suggesting that women who did not live with a partner/spouse or who had low household income were more likely to report being affected by bushfires.

"Similarly, no associations with setting (urban/rural), parity, or trimester were detected."

The study authors - who work at the Australian National University, Canberra Health Services, the University of Canberra and the University of Sydney - said the findings showed the need for more mental health supports.

"Consequently, the development of interventions to increase awareness of this risk before such disasters occur and the implementation of support structures to mitigate this risk during and after bushfires should be considered, particularly in the context of intensifying bushfires due to climate change," the group's paper said.

The findings from the study were published last week in the peer-reviewed International Journal of Environmental Research and Public Health.