Leading Australian dealer of Indigenous art Tim Klingender has been found dead in Sydney Harbour following a suspected boating accident.

Friends and associates confirmed the body found at Watsons Bay in Sydney’s east on Thursday to be that of the 59-year-old.

Melbourne gallerist D’Lan Davidson said Mr Klingender was “the architect of the market we have today”.

“He leaves behind a huge vacuum for Indigenous art in this country and around the world,” he said in a statement on Friday.

Friends said the art dealer, a married father of two, had gone out on a boat for a fishing expedition early on Thursday morning.

The Marine Area Command initially responded to reports of boating debris floating in the water off Watsons Bay about 10.20am on Thursday.

Officers found the body of a man in the water, police said in a statement on Friday.

Investigators are being assisted by PolAir and Rescue Squad to search for a second man, 51, who was believed to have also been in the vessel.

Mr Klingender was employed as the international director of Sotheby’s between 1998 and 2009.

He founded Sotheby’s Aboriginal art department in 1996, touring works internationally before their auction in Australia.

Gallery owner and art dealer Michael Reid shared another heartfelt tribute to Mr Klingender, with “profound sadness”.

“The death of Tim Klingender was an unimaginable and devastating loss to his family and indeed the Australian art world,” he wrote on Facebook on Friday.

“With Tim’s death … so much knowledge has just ended.”

Mr Reid said Mr Klingender’s funeral will be “massive, as friends from just so many walks and corners of his life gather”.

“Many will not know each other; however, Tim knew them all and well. Rest amongst us Tim,” he wrote.

– with AAP