Jackman plays the title character in the film. He has played Wolverine in three previous "X-Men" blockbusters.
While promoting the soon-to-be-released next installment in the franchise at Cockatoo Island in Sydney Harbor Tuesday, the Australian actor said he was "heartbroken" over last week's leak, the BBC said.
"There's no doubt it's very disappointing. Obviously, people are seeing an unfinished film," Jackman said, comparing the working copy of the movie to a "Ferrari without a paint job."
An investigation into who leaked the film is under way. The movie is estimated to have been downloaded 100,000 times from file-sharing Web sites, the BBC noted.