Photos: Six-months-old platypus captured and released in Royal National Park project

A six-months-old platypus has been captured, checked over, microchipped and released back into the water in Royal National Park.

The move comes less than a year after ten of the mammals were reintroduced to the park where they had been locally extinct for more than 50 years.

The female was captured during a survey to assess the health of the translocated platypuses and confirm potential offspring.

Over three nights, researchers from UNSW Sydney, Taronga Conservation Society Australia and WWF Australia, with the support of NSW National Parks and Wildlife, laid nets in 'hot spots' along the waterways of the Royal National Park.

They were placed in areas where monitoring had indicated regular activity.

Minister for Climate Change and the Environment Penny Sharpe said, "This is a wonderful discovery by our dedicated scientists and researchers, who have spent their nights patiently monitoring the Hacking River for signs these platypuses have survived in their new home".

Ms Sharpe said the little platypus was in excellent condition, weighed in at 850 grams and was estimated to be about six months old.

"Her age aligns with the end of the platypus breeding season and means she would have only just emerged from her burrow," she said.

"She will be named by the local Indigenous community.

"Before she was returned to the river, researchers assessed her body condition, took several samples and fitted her with a microchip for future identification."

Ms Sharpe said, during the surveys, researchers also captured an adult female platypus named Delphi in the same area, who was also in good condition.

"Genetic analysis will confirm the juvenile's parents, providing valuable insights into the breeding patterns and genetic health of the population.

"Ongoing monitoring and tracking have confirmed all ten of the original platypuses are still active, with a couple recently venturing beyond the detection range.

"The research team has not ruled out the possibility of more juveniles in the area."

Ms Sharpe said the waterways in the Royal National Park had been extensively monitored, with results indicating habitat, food availability and water quality is suitable for supporting healthy populations of platypuses.

"The breeding success is a significant milestone for the program and testament to the health of the park. Further reintroductions are planned over the coming years," she said.

The return of platypus to the Royal National Park was the first translocation program for platypus in NSW and aimed to re-establish a self-sustaining and genetically diverse platypus population.

The platypuses were sourced from across NSW to ensure genetic diversity and taken to Taronga Zoo's purpose-built platypus refuge before being released into the park.