The British family and pilot aboard the ill-fated Sydney Seaplane that crashed on New Year's Eve died of head injuries and drowning, a UK coroner has revealed.

The seaplane, piloted by Canadian Gareth Morgan, crashed into the Hawkesbury River on December 31 with high profile UK businessman Richard Cousins and his family on board.

The six victims of the Sydney Seaplane crash.

There were no survivors.

The Australian Transport Safety Bureau and NSW Coroner are both conducting investigations into the fatal incident but the coroner in Reading, UK, officially opened an investigation on Monday.