Six people have died after a seaplane crashed into the Hawkesbury River north of Sydney, NSW Police have confirmed.
The Sydney Seaplanes aircraft was carrying a pilot and five passengers when it crashed at Cowan Creek, Jerusalem Bay, on the Hawkesbury River about 3pm on Sunday.
Emergency services including the Westpac Life Saver Rescue Helicopter were called to the scene with police commencing a search and rescue operation to locate the plane, which is submerged.
NSW Police confirmed that divers have recovered the bodies of all six people aboard the plane.
"(We will) see if we can recover the plane tonight or whether it will stay in situ ... until tomorrow morning," acting Superintendent Michael Gorman told reporters on the scene on Sunday.
"We don't know why the plane crashed."
The plane was believed to have been travelling from the picturesque Cottage Point Inn to Rose Bay, Supt Gorman said.
The ages and identities of those aboard the plane are unknown.
"(There) certainly were people out on boats and on the water which is why if people have seen what occurred please contact marine area command or crime stoppers," Supt Gorman said.
A Sydney Seaplanes spokesman told AAP the aircraft was one of theirs and said they were working with police on the scene.
The Westpac Life Saver Rescue Helicopter found an oil slick and several items of debris on the surface of Cowan Creek, spokesman Stephen Leahy told AAP.
"There appeared to be a silhouette or outline of a small aircraft but it appeared to be submerged in deep water," he said.
"It was certainly too deep for us to access it and that's why the police divers have been called in."
The Australian Transport Safety Bureau has announced it will investigate the incident.
The company, which has been operating for 80 years, provides flights above and around some of Sydney's most popular tourist sites including the Opera House, the Harbour Bridge, Pittwater and the Hawkesbury River region.
