Wildlife ecologist Josh Griffiths said the eDNA testing involved analysing water samples for traces of aquatic life through discovery of genetic material such as shed skin cells.

"This lower section of the river is in good condition and the eDNA results have shown that the platypus population has definitely moved further downstream," he said.

"The eDNA test is highly sensitive and is a much more efficient method for discovering platypus and seeing if they have recolonised in areas where they disappeared during the millennium drought."

The research will be carried out throughout this week.

"The sampling is usually carried out in the morning so that they are not trapped in through the night. We want to make sure that they spend as little time being contained," Mr Griffiths said.

Mr Griffiths has been monitoring the platypus population since the past 12-years. The water testing will be conducted across the stretch of the river and project management is hoping to get some positive results this year.

Although there are no statistical figure to represent the growth, the project has noticed traces of expansion during the sampling over the years.

"We don't see a massive spike in our catch rates but in the last six years, we have caught about seven juveniles which we hadn't seen for almost a decade. The fact that they are reproducing is very good sign to continually see new animals in the system."

Greg Fletcher, the authority's project and planning officer, said there were a handful of platypus in the region.

He said this project aimed to regulate environmental flows and sustain the platypus population. Wimmera CMA has been working on this project for the last 10-year to curate an environment regime which will help balance the ecosystem.

He said that the eDNA method has been identified as useful method to track other marine wildlife in the Wimmera region.

Wimmera CMA said the residents could report platypus sightings via platypus SPOT online at www.platypusspot.org or via the platypusSPOT app.