Scientists say bushfires and drought have taken a further toll on the near-threatened platypus.
The research commissioned by the World Wide Fund for Nature Australia found numbers of the monotreme had further declined after the 2019/20 bushfire crisis.
Researchers from the University of New South Wales surveyed platypuses on the Mid-North Coast of NSW in July and August 2020, seven months after a severe drought and bushfire impacted the area.
The study compared platypus numbers in a burnt river catchment to an unburnt catchment.
In the burnt sections of the Dingo, Bobin and Bulga Creeks, researchers recorded only two platypuses while in the nearby Thone River - which escaped the fires but was similarly impacted by the drought - they caught seven.
Dr Gilad Bino from UNSW was part of the team who conducted the research and said they spent two weeks surveying the area.
"What we found was in the fire impacted areas, platypus numbers were extremely low ... and that was heavily contrasted with higher numbers in the areas that were not impacted by the fires," he told AAP ."
"Seven months after the fires, we found significantly fewer platypuses in burnt waterways compared to unburnt ones."
Dr Bino said while it was a small sample size it is indicative of what was happening on a broader area.
"There is strong evidence to suggest the extreme drought ... and then the fires ... and then a lot of ash being deposited into the creek, we think those combinations had a significant impact on the platypus there."
During two weeks of surveys, his team failed to observe any juveniles despite it being a few months after the breeding season, Dr Bino said.
The WWF study will see scientists return to the area again next month to conduct further research, including whether the platypus has begun breeding in the area again.
Dr Kita Ashman, WWF-Australia Threatened Species and Climate Adaptation Ecologist said the findings are extremely worrying.
"Given research has recently shown platypus populations have declined by a third in the past ten years, any further threat to the platypus is a real concern," she said.
"The fires and drought have really devastated platypus populations, drought has been a long-term threat and then the fires were a nail in the coffin for a lot of platypus populations.
"It's unlikely the platypus has simply moved further downstream... some individuals could have moved but it's more likely the individuals perished in the fires, or died due to habitat degradation."
More needs to be done to help the platypus, by not altering the platypus' natural habitat and giving the animal "increased protection," by lifting it's near threatened status, she said.