Martial arts star Jet Li has injured himself while shooting a fight sequence for his latest action movie, "Fearless".

The incident occurred when a terrified stuntman lost his balance and the pair tumbled off a building.

The director of the film Ronny Yu admits that he feared the worst when the fight scene went awry and his leading man and a stuntman took a tumble off a building.

"Everybody was so scared to fight with him, but we had everything choreographed. Before filming I had a long conversation with Jet and we decided to do it all as real as possible, so we used wirework just for safety because there was a tower fight, which was dangerous.

"The mattresses on the bottom helped, but he was so high up. Jet had an accident. One day we were supposed to do a very simple move up there and I was watching the monitor and all of a sudden I couldn't find Jet. He fell, because his opponent was so scared of him," Yu said.

"Once the camera started rolling he (stuntman) wanted to do it quick, rather than do 10 moves; he just pushed him (Li) and they both fell - and missed the mattresses. Luckily, it was grassland and soft mud so Jet probably just got a bruised bum," he added.

The "Romeo Must Die" actor, 43 had recently claimed that he would quit making martial arts movies because he has tired of hurting himself and others. He said age is catching up with him and he has begun to feel the aches and pains of a lifetime of martial arts training.

"My older injuries bother me all the time. I just feel when I was eight years old and I was learning martial arts it was fine, and now it has taken up 90 per cent of my life's learning. I never graduated. Physically and mentally, sometimes I feel tired. The biggest enemy is yourself," he said.

"They never say I hurt them. They always say, 'I'm OK, I'm fine.' They want to make another movie again. Martial artists get hurt all the time but they don't say, 'I got to go home, don't call me.' They all put on these oils to fix it behind the scenes. Everybody hurts each other," he added.

Editor: Donald