The managing director of the flight company, Aaron Shaw, said full co-operation is being provided to authorities as they investigate the cause of the crash.
“We are confident that we have done everything we possibly can,” he said.
“The police have asked for a number of documents which we provided immediately and will continue to do so to any other relevant agencies.”
The plane crashed into the Hawkesbury River, near the suburb of Cowan, some 50 kilometres north of Sydney on New Year’s Eve.
The bodies of those on board have been recovered and the victims identified by police. They include a British family of five and the pilot.
Experienced Australian pilot Gareth Morgan was flying the plane carrying the family of the chief executive of the world's largest food catering company, Compass Group.
Richard Cousins had just finished lunch with his two sons, fiancé and her 11-year-old daughter when they boarded the DHC-2 Beaver Seaplane from Cottage Point Inn.
The destination had been Rose Bay in Sydney Harbour.
The 58-year-old businessman had been sighted by Sydney Seaplanes staff before he boarded the plane with sons 23-year-old Edward, 25-year-old William Cousins, fiancé Emma Bowden, 48, and her daughter, Heather Bowden-Page.
The company has confirmed it has suspended its fleet of four planes until further notice. Refunds are being provided to people who booked flights, which are now cancelled.
Aaron Shaw said all the safety protocols had been followed, including daily checks and regular maintenance of the 1964 model aircraft.
“These aircraft are some of the most widely used seaplanes in the world today. We operated two of those until yesterday. Hundreds have been operating all over the world.”
Sydney Seaplanes has been operating since 2005, and flies 27,000 passengers annually. The $300-a-head service has been used by high profile customers, including Pippa Middleton, sister of the Duchess of Cambridge, who used the service during her honeymoon with husband James Mathews in June.
Aaron Shaw said he does not believe the incident will completely dismantle the reputation of sea planes.
“The public will make their own decisions on that. We have had an unblemished safety record until now, sea planes are considered one of the safest aircraft in the world and remain that way.”
Police are still examining the crash site and have appealed for witnesses to come forward with any information.
The submerged plane will need to be recovered before forensic air-crash investigators can determine the cause of the crash.
The Australian Transport Safety Bureau (ATSB) said it would launch its investigation once police handed over the scene, and it aims to file a preliminary report by the end of the month.
‘Tragic loss’
Detective Superintendent Mark Hutchings, from the New South Wales Police Marine Area Command said it is a tragic outcome for all involved.
“I think the incident ... talks for itself,” he said.
“These are people who have come over on holidays to visit Australia. They were in one of the most beautiful parts of the world and for this to happen to them at a place like that is nothing more than just tragic.”
Prime Minister Malcolm Turnbull, whose father died in a light plane accident, said his thoughts and prayers are with the family.
"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.
Aaron Shaw paid tribute to Richard Cousins as a “lovely” and “gentle” guy. He said breaking the news of his death to the parents in Canada had been difficult.
“He was deeply liked by all of our staff and me personally. We are all absolutely devastated at his loss and bringing his parents today was obviously one of the worst calls that I have ever had to make in my life.”
Counselling services have been provided to the Seaplanes staff.
Compass Group chairman, Paul Walsh, said the company was "deeply shocked and saddened” by the death of the company’s chief executive.
"The thoughts of everyone at Compass are with Richard's family and friends, and we extend our deepest sympathies to them," he said.
"Richard was known and respected for his great humanity and a no-nonsense style that transformed Compass into one of Britain's leading companies."
