By James Pearson

SEOUL (Reuters) - The comedy on the fictional assassination of North Korea's leader is "desperately unfunny" and would have flopped overseas if it had not been canceled, according to leaked e-mails of international executives of Sony Pictures.

Sony Corp scrapped its Christmas Day release of "The Interview," following threats by hackers who have leaked internal company documents and emails, as well as unreleased movies, on the internet. U.S. government sources have said investigators had determined the attack was "state sponsored" and that North Korea was the government involved.

But even before the cancellation of the film, Sony executives responsible for the international release of the movie were concerned the action-comedy featuring Hollywood stars Seth Rogen and James Franco would not translate to a foreign audience, the leaked e-mails show.

Reuters has not been able to verify the authenticity of the documents, although Sony has confirmed that at least some are authentic.

"The unanimous point of view here is that this (is) another misfire from the pairing," said an e-mail purportedly written by Peter Taylor, of Sony Pictures UK.

Taylor said the film was "desperately unfunny and repetitive," and "James Franco proves once again that irritation is his strong suit which is a shame because the character could have been appealing and funny out of his hands."

Taylor and other executives agreed that the first half hour of the film, which features a satirical interview with hip-hop artist Eminem, was amusing but was later overshadowed by "realistic violence that would be shocking in a horror movie".

Staff in Holland said the film was "unbalanced," and a French executive said the film went too far. "Seth Rogen's humor doesn't really translate," the executive said.

South Korean colleagues raised concerns over the potential political issues and inaccuracies in the North Korean accents used in the film, and said the leading actors were "weak".

Sony staff in Taiwan said the film "didn't stand a chance" in their market, according to the e-mails. Australian executives, however, enjoyed the film and requested lead actor Franco lead a promotional tour of the country.

British executives were less enthusiastic.

"Tour-wise, our choice would be to have no one. However if this is not an option (and I suspect it isn't) then we would like the lot," Taylor said.

"Not just Rogen and (writer Evan) Goldberg, but God help us Franco as well."

Film review website RottenTomatoes.com gave the movie an average rating of 6.4/10 based on 26 film critic reviews.

(Editing by Raju Gopalakrishnan)