"Iron Man 3" topped Chinese box offices five days after opening, state media reported on Tuesday, but the modified domestic version of the Hollywood blockbuster has raised some eyebrows.

The film starring Robert Downey Jr as the hero Tony Stark has earned 410 million yuan ($67 million) since last Wednesday, when it broke a national record with opening-day sales of 116 million yuan, Xinhua news agency said.

The Chinese release had four extra minutes, including the product placement of a local milk drink called Gu Li Duo touted as a source of Iron Man's energy, the Hollywood Reporter said.

Also unique to the Chinese version was the appearance of "Dr Wu", a character played by local actor Wang Xueqi, who in his limited screen time drinks a carton of Gu Li Duo and performs an operation on Stark.

Chinese viewers felt the added bits were "superfluous to the narrative", the Hollywood Reporter said.

There was no immediate explanation for the additions. Chinese authorities normally cut foreign films, due to sexual and political sensitivities, rather than add to them.

In April the country's cinemas abruptly cancelled all screenings of Quentin Tarantino's "Django Unchained" just as it was released, with one viewer adding that a showing was stopped after just one minute.

Nudity of the main character played by Jamie Foxx may have prompted the sudden censorship, the popular web portal Sina said at the time.

Scenes were also cut from the latest James Bond film "Skyfall", including a killing in Shanghai, along with mentions of prostitution in Macau and torture by Chinese security agents.