The cast list includes Canto-pop heart-throbs Aaron Kwok Fu-shing and Ekin Cheng, but the real 'star' of the show is undoubtedly the dazzling effects.

'Hong Kong action films were very good in 1992 or 1993 but they were mainly fists and legs. These days, that won't work,' says producer Manfred Wong. 'We have to change the old methods. Kids these days love playing computer games which are so vivid, and they will only go to a movie they think is different from conventional ones.' At a sneak preview of selected scenes at Centro Digital Centre's hi-tech headquarters in Yau Yat Chuen, the special effects in The Storm Riders look impressive.

Centro, one of the film's two financiers (the other being Golden Harvest), had previously provided computer generated effects for other movies such as The Umbrella Story and The Soong Sisters, but The Storm Riders has been their biggest film project so far.

Over 500 scenes, totalling 40 minutes of action, required computer-generated effects and, certainly, it would have been extremely difficult to bring Ma's fantasy-laden kung fu comics to life with current restraints on local film-making.

Set in ancient China, the story revolves around Xiong Ba (Sonny Chiba), a martial arts expert intent on conquering the world. A fortune teller informs him that he needs to find the elements Wind and Cloud to achieve his ambitions. Xiong tracks down the unrelated Whispering Wind (Ekin Cheng) and Striding Cloud (Aaron Kwok), kills their parents and brings the children up as his disciples.

When they grow up, however, they discover their master is actually their enemy and Xiong also learns the second half of his prophecy - Wind and Cloud will make you and break you - thereby setting the scene for a final showdown.

Director Andrew Lau Wai-keung, best known for churning out the low-budget Young And Dangerous triad series, agrees that The Storm Riders would not have been possible without the computer-generated effects.

'There were many places where we could never have shot those scenes. For most of these, we had to revert to CGI [computer generated imagery]. The budget would have been a lot more if Centro had not been one of the investors and had charged us the full amount,' Lau said.

One of the fight scenes takes place on top of the 71-metre Great Buddha in Leshan, Sichuan, filmed with what appears to be a 360-degree revolving camera. In reality, the 'fight' took place in a blue-walled room, with the characters on a revolving plank. The figures were later scanned onto the computer image of the Buddha.

'That would have been logistically impossible to film, not only because of the tourists but also because of the height of the Buddha,' explained visual effects director, Mike Wong Kin-ming, whose job it was to help merge special effects with live action.

One of biggest challenges in The Storm Riders, for both Lau and Wong, was creating the mythical Fire Kirin, a fire-breathing creature that duels with Wind. 'We had to rely a lot on just computer graphics because we could not afford to build models. It was a challenge recreating on the computer scenes we had shot,' explained director Lau.

Wong added: 'We needed to keep the texture of the scales on its skin while depicting its fiery body and there were a lot of facial expressions and little actions such as twitching muscles. That was a really big challenge.' For actor Cheng, the shooting scenes also proved quite a task because - like actors who have worked on Jurassic Park or Twister - he had to act and fight against something that was not there.

'I had to rely a lot on my imagination and what I remember from the comic books,' said Cheng. 'I had to guess where it should be and imagine what it would feel like being scorched by it. I've never done it before and it was rather fun.' But Lau added: 'Luckily, we didn't have to re-shoot many of the scenes. We could rely on the computer to get rid of irregularities in some of the shots, such as the more modern architecture in the background. It all seems like magic now.' The Storm Riders has been Lau's biggest project so far and has taken more than two years to complete. The script took five versions and more than half a year to finalise and three storyboard versions followed. Location shooting alone took four-and-a-half months, while post-production and CGI has taken almost nine months.

It is a far cry from some of the Young And Dangerous series which took about a month from pre-production to release.

Lau, who calls The Storm Riders his 'costume drama Star Wars', had everything done locally. He is hoping the film will put the Hong Kong film industry on the global map again. 'I wanted the label 'Made in Hong Kong'. I don't want to give face to Hollywood; I want to show them we can do it here and at such a low cost [compared with theirs].' And, as John Chu Kar-yan, Centro's CEO and one of the film's executive producers, says: 'It is time for Hong Kong-produced CGI to be used in Hong Kong films so that people know it's not only Hollywood that can do it.' But whether the story will live up to the film's expensive special effects will be something that can only be determined when it is released next week.

The Storm Riders opens in Hong Kong on July 16.

Cover illustration of Kwok and Cheng by Winnie Ho