Australian filmmaker Baz Luhrmann has told a gathering of cinema owners and operators in Barcelona he knows how important it is to get them on side, as his family once owned a cinema in rural NSW.

The Hollywood Reporter website says Luhrmann was speaking to CineEurope via a video message.

He said the extended clips they were about to see of his 3D version of The Great Gatsby were "very raw", but there was an enthusiastic response afterwards from those assembled.

The film is set to start hitting international cinemas in December.

The audience was also treated to excerpts of Sir Peter Jackson's The Hobbit: An Unexpected Journey.