Two women have died after they were washed off rocks into the ocean in Sydney's south.

Emergency services were called to Cape Solander at Kurnell in the Sutherland Shire about 4:30pm on Monday, following reports three women had been swept into the water.

One woman was able to climb onto rocks and was helped by members of the public back onto the shore.

NSW Police with assistance from PolAir searched the ocean for the other two women.

They were both found unconscious and pulled from the ocean.

Paramedics and a Toll Helicopter doctor treated the women at the scene but they were unable to be revived.

Police have launched an investigation into the matter, but no suspicious circumstances have been identified in relation to the deaths.

The women are yet to be formally identified.

A report will be prepared for the coroner.

A police source told the ABC they believed the women were not fishing as there was no equipment found at the site.

It comes exactly two weeks after two rock fishermen drowned after also being swept off the rocks around the same area in Kurnell.

The pair were later identified as Nepalese nationals aged in their 20s.

Royal Life Saving Society CEO Justin Scarr said the deaths were "absolutely tragic for all involved".

"We do know that people underestimate the risks of slippery rock faces on incoming tides, on waves, and wave action in and around rock platforms," he said.

"Quite often people get themselves in trouble by simply being unaware of the risks."

Mr Scarr said the area where the drownings occurred was known as a "black spot".

"Royal Life Saving and Surf Life Saving identify black spots for drownings all across the country that includes places on beaches but also rock platforms and inland waterways," he said.

"The programmes are generally looking very carefully at the people that are drowning in those locations and initiating a range of responses including public awareness campaigns, dealing directly with community members, and also in some cases putting in signage and increasing rescue responses."

Westpac Life Saver Rescue Helicopter general manager Shane Daw said the organisation wanted to remind people to "watch out for waves, watch out for slippery rocks and surfaces".

"We're really urging the public and anybody in those areas, think about where you're going and potentially the risk that is posed by you climbing over those rocky areas," he said.