Cost of making Hobbit movies up to $870M

The movie trilogy The Hobbit has so far cost nearly three-quarters of a billion US dollars to make as the epic continues to set new benchmarks for studio spending.

Financial documents filed this month in New Zealand, where the films are being made, show production costs through March had reached $NZ934 million ($A869.52 million).

That eclipses previous records for film productions. On a per-film basis, however, the movies are not the most expensive ever. At least not yet.

Box Office Mojo and Guinness World Records estimate that record goes to Pirates of the Caribbean: At World's End which cost $US300 million.

Box Office Mojo estimates the first two Hobbit movies took in a combined $US1.98 billion at the box office.

Distributor Warner Bros declined to comment.