A water-skier was unable to be revived after being injured on the Hawkesbury River at Wilberforce.
Emergency services were called to the the river at Pitt Town about 3.40pm on August 14, police said in a statement.
"Officers attached to Hawkesbury Police Area Command and NSW Ambulance paramedics arrived to locate a man with leg injuries in a boat, who was unable to be revived and died at the scene," police stated.
"Police have been told the man was injured while water skiing on the river at Wilberforce.
"Three other men were with the man at the time of the incident, who were all uninjured."
The driver of the boat was taken to Hawkesbury Hospital for mandatory testing, police stated.
Inquiries into the incident are continuing.