A man has died and three other people, including a child, have been rescued after their boat sank in Sydney Harbour.
A cruise ship called police after discovering three men and an eight-year-old boy in the water near Shark Island at about 7.50pm (AEST) on Saturday.
The boy was pulled from the water before police arrived and an officer later jumped in to rescue the men, one of whom was unconscious, police said.
He was unable to be revived and was pronounced dead by paramedics before they reached Rose Bay Wharf, police said.
The boy and the other two men were uninjured and will be interviewed by police to establish why the tragedy occurred.
Police divers will attempt to locate the vessel on Sunday.
The dead man has not yet been formally identified.