Witnesses reported 39-year-old Senior Constable Kelly Foster was attempting to rescue the woman who'd been swept off an inflatable lilo into a whirlpool at Mount Wilson on Saturday afternoon.

The younger woman is yet to be named but is believed to be a 24-year-old international student who was living in Chiswick, in Sydney.

NSW Police Minister David Elliott released a statement on Sunday saying Sen Const Foster had lost her life coming to the aid of another, a truly heroic act that would never be forgotten.

He said her death was a sincere loss for her family, community and the NSW Police Force.

Sen Const Foster first joined the police a decade ago. She had worked for State Crime Command as an intel officer until May last year, but most recently was stationed at Lithgow.

She took a break in her career after being diagnosed with breast cancer.

Acting Commissioner Mal Lanyon said her return to work was a testament to her strength and resilience.

"To hear reports that Kelly was trying to help another woman when she died demonstrates her commitment to the community she served and the ability to put the needs of others before her own," he said.

"Above all, Kelly was a kind and loving daughter, sister and partner."

Police and ambulance crews rushed to the scene on Saturday but had to suspend a search at 6 pm because of poor weather.

The search resumed on Sunday morning with help from police divers, and the bodies were found around midday.

No other members of the canyoning group were injured.

Australian Associated Press