A woman in her 40s was treated at the scene, located in the Wollondilly Shire, but could not be revived, NSW Police said in a statement on Saturday night.

A second woman, also aged in her 40s, was treated by NSW Ambulance paramedics and taken to Liverpool Hospital where she remains in a serious but stable condition.

The tragedy comes after parts of the state were hit with a severe weather warning for a “very dangerous thunderstorm” bringing intense rainfall, large hailstones and damaging winds.

Following the Bureau of Meteorology’s weather warning, the SES asked residents in High Range, Robertson, Colo Vale, Hill Top and Bowral to “stay indoors” as the storm passes.

The system impacted Nattai National Park, Yerranderie and the Nattai Tablelands before moving northeast towards Oakdale, the western parts of the Wollondilly Shire and the area west of Picton.

A severe thunderstorm warning is currently in place for people in parts of the Hunter, Illawarra, Central Tablelands, Southern Tablelands and North West Slopes and Plains Forecast Districts.

The severe thunderstorm, which are likely to produce heavy rainfall that may lead to flash flooding, is gradually easing, the bureau said in its latest update to residents.