A young woman has died after plummeting off the 10th floor balcony of a hotel in Sydney's south, landing on a balcony on the second floor.

The 21-year-old was taken to hospital with serious injuries but died early on Thursday morning, police said.

Emergency services were called to a hotel on the Kingsway at Cronulla about 11.30pm (AEDT) on Wednesday.

Police are now investigating the circumstances surrounding the woman's death and a coronial report is being prepared.