Auckland-based Smith suffered severe head injuries in a fall in the Chinese capital 10 days ago.
The accident occurred on February 6, the day after the 38-year-old finished work on a joint United States-Chinese film production, and as he was preparing to return to New Zealand.
Smith was then to have headed to a movie "boot camp" to prepare for what many believed would be his big break, a role in a Hollywood blockbuster starring Bruce Willis.
The doctor treating Smith told the New Zealand Herald last night that staff from China's top movie production house, Beijing Film Studio, rushed him to the Beijing Union Hospital after the fall.
The doctor, who did not wish to be named, said Smith had suffered a severe injury to his skull and was in a critical condition.
Acting sources have said he was injured when he fell from a great height, possibly six storeys.
His agent said the fall did not occur on the set of the martial arts movie.
Smith had starred in many New Zealand stage, television and feature films and is perhaps best known for his role as Ares in Xena: Warrior Princess.
His ambitions to break into the American movie market were realised when he scored a role in the $US70 million ($166 million) Bruce Willis action film Man of War, due to start filming in Hawaii next month.
He had leaped at the chance to go to China because the role allowed him to learn from the stuntman who worked on Crouching Tiger, Hidden Dragon. - Radio New Zealand/NZPA