A high-profile British CEO and his family were among six people killed in a New Year's Eve seaplane crash in Australia, police said on Monday.

The plane went down Sunday in the Hawkesbury River near the suburb of Cowan some 50 kilometres (31 miles) north of Sydney, as New Year's revellers on the banks watched in shock.

The bodies of all of those on board -- one pilot and five passengers -- have been recovered from the wreckage, with Richard Cousins, chief executive of British catering giant Compass, identified as among the deceased.

Cousins' two sons in their early 20s and his fiancee and her 11-year-old daughter were also killed in the crash.

"The thoughts of everyone at Compass are with Richard's family and friends, and we extend our deepest sympathies with them," Compass group chairman Paul Walsh said in a statement.

Cousins, who was recently named by Harvard Business Review as one of the world's best-performing CEOs, was due to step down from Compass this year.

New South Wales detective superintendent Mark Hutchings said all passengers on board were British nationals and the pilot Australian.

The cause of the accident remains unknown with the investigation ongoing.

Witnesses recalled seeing the aircraft, a DHC-2 Beaver Seaplane which was heading to Rose Bay in Sydney Harbour, do a sharp turn before plummeting straight into the water.

Prime Minister Malcolm Turnbull, whose father died in a light plane accident, paid his respects to the families of those killed.

"We grieve for those who've lost their lives, and again, our thoughts and prayers are with their families as they come to terms with this terrible loss," he said.

The flight company Sydney Seaplanes has suspended its operations until further notice.

Source: AFP