Hopkins, 53, from Greytown, New Zealand, died after being thrown from his raft on Sunday, said the Hollywood Reporter.
The accident happened in the Waiohine River on New Zealand's North Island. His two rafting companions both survived.
"Police would like to thank all those who assisted in the recovery of Mr Hopkins and the rescue of his companions, particularly the jet boat operator who came to our aid and, at considerable risk to himself, was able to rescue the female.
"All three were wearing life jackets, wetsuits and helmets at the time and it appears that Mr Hopkins got into trouble after they were ejected from the raft in a fast flowing eddy," said police senior sergeant Carolyn Watson.
Hopkins won Academy Awards for his work on 'The Lord of the Rings: The Two Towers' in 2003 and 'King Kong' in 2006. He also worked on 'Blade Runner', 'Superman', 'Octopussy' and 'Transformers'.
Hopkins first worked with director Peter Jackson on his 1992 movie 'Braindead', and was also part of Jackson's team for 'Heavenly Creatures' and 'The Frighteners' as well as the three 'Lord of the Rings' epics.
Hopkins shared his two Oscar wins and one further nomination with US collaborator Ethan Van der Ryn.
