The company operating the seaplane said the weather on Sunday had been benign and the pilot "extremely experienced".
Five British vacationers including the head of the world's biggest catering firm have been killed in a New Year’s Eve seaplane crash near Sydney.
Police named the victims as Richard Cousins, 58, CEO of the British-based catering and food services giant, Emma Bowden, 48, Heather Bowden, 11, Edward Cousins, 23 and William Cousins, 25.
Australian and British media reports identified the victims as the CEO's two sons, his fiancée and her daughter.
The plane's Australian pilot Gareth Morgan, 44, was also killed when the plane plunged into the Hawkesbury River near Cowan, north of Sydney.
Prime Minister Malcolm Turnbull offered his condolences to the families of the victims, calling the crash “a tragedy”.
Authorities have opened an investigation and are trying to recover the wreckage of the plane, which is submerged in 13 metres of water.
The plane's operators, Sydney Seaplanes, have suspended all flight operations until the cause of the crash is identified.
The company said the weather on Sunday had been benign and the pilot had completed the trip "hundreds of times."
"He was an extremely experienced pilot with over 10,000 hours' flying time of which 9,000 hours were in sea planes. On a personal level, he was deeply respected and liked by me and all of the team at Sydney Sea Planes," said Aaron Shaw, the firm’s managing director.
Compass Chairman Paul Walsh said in a statement: "The thoughts of everyone at Compass are with Richard's family and friends, and we extend our deepest sympathies to them."
"Richard was known and respected for his great humanity and a no-nonsense style that transformed Compass into one of Britain's leading companies," he added on Monday.
Cousins, who led Compass over the past 11 years, was due to step down in March. He has been widely credited with turning the company's business around and making Compass into one of the Financial Times Stock Exchange's best-performing firms.
Cousins had also been named as one of the world's best-performing CEOs by Harvard Business Review.