The 87-year-old Academy Award-winning writer of The King's Speech passed away on Saturday, his longtime manager Jeff Aghassi said.
No cause of death was given.
'David was in the place he loved most in the world – New Zealand – doing what gave him the greatest peace which was fly-fishing,' Mr Aghassi told Deadline.
"If given the chance, it is exactly as he would have scripted it."
The King's Speech, released in 2010, centres on the future King George VI who strokes up a bond with an Australian speech and language therapist when seeking a remedy to his stammer.
The film was a major box office success and won four Oscars,