The chief executive's interest in the film suggests the company's leadership was worried about Pyongyang's objections even before a devastating cyber attack on Sony's Hollywood studio network last month.

A Sony official said Hirai rarely reviewed specific scenes in films.

North Korea complained to the United Nations in July, accusing the US of sponsoring terrorism and committing an act of war by producing the movie.

In an exchange with writer and co-director Rogen, Pascal said she was in a difficult position because Hirai had asked her to make changes in the film.

"And this isn't some flunky. It's the chairman of the entire Sony Corporation who I am dealing [with]," she said.

Rogen responded by promising to remove three of four burn marks on Kim's face, and reduce the "flaming hair" by 50 per cent. But he said he could not meet all the demands.

"The head explosion can't be more obscured than it is because we honestly feel that if it's any more obscured, you won't be able to tell it's exploding and the joke won't work," he said.

Representatives for Rogen declined to comment.

In a scandal that has sent shockwaves through the entertainment industry, hackers have released reams of sensitive Sony information on the internet.

Rogen initially told Pascal he objected to requests to modify the death scene, which he said would be viewed as censorship and hurt sales.

"This is now a story of Americans changing their movie to make North Koreans happy," he said in an August 15 email. "That is a very damning story."

By October, however, he delivered what he hoped was the final version.

"We removed the fire from the hair and the entire secondary wave of head chunks," he said. "Please tell us this is over now."

The movie is due for release in the US on Christmas Day.