China's Internet censors may have kept most of the nation's 420 million web users from accessing Facebook, but they have not stopped social game developers like Ellison Gao.

Five Minutes, a Shanghai-based studio co-founded by Gao, 27, launched its first social game two years ago and has attracted millions of dollars from investors, including US venture capital firm Draper Fisher Jurvetson.

"It is impossible for any Chinese developer to ignore the Facebook market, just as it is for all the other social game firms across the globe," Gao told AFP at an industry forum last week.

More than a million users play his studio's games each day on Facebook, the firm's biggest market, although it has also moved onto local platforms in Brazil, Japan, and South Korea, Gao said.

Social games, which are usually free to play, are one of Facebook's most popular features. Games such as Zynga's FarmVille, in which users interact as they manage virtual farms, have become global hits.

Developers and social networking websites share revenue they generate from selling virtual goods and in-game advertising.

Gao's firm is not the only Chinese company prospering on Facebook, which is blocked along with websites like YouTube and Twitter by China's vast system of Internet censorship, dubbed the "Great Firewall".

Beijing-based studio Happy Elements has an average of more than 2.2 million daily Facebook users while rival studio ELEX has about 1.3 million, according to tracking firm Inside Network.

Chinese game studios are swarming to Facebook, which collects a 30 percent share of revenues -- terms developers say are more favourable than those of domestic sites -- and offers an open platform with over 500 million users.

"It is not surprising that smaller companies are the ones taking the risks to develop for the Western market", said Andrew Mo, head of product management at the Beijing studio of London-based social network game maker Playfish.

"Unless you are a big company in China, it is hard to get that relationship with different social network platforms in order to get a good revenue share-split."

Facebook has an estimated 14 million Chinese-language users, mainly based in Taiwan, Singapore and Hong Kong. That number is expected to grow to 16 million by March, according to the Inside Network site that reports on Facebook.

The success of Chinese game studios on Facebook has also spurred Western social networking game developers like Zynga to set up shop in China to tap a growing pool of talented programmers.

San Francisco-based Zynga established a Beijing studio in May by acquiring local firm XPD Media, while US videogame maker Electronics Arts last year bought Playfish, which has been in Beijing since 2007.

"As we combine the web and games, it makes sense to build up a studio here to develop for the global market," Andy Tian, head of Zynga's Beijing studio, told a packed hall at the forum.

Three months after announcing the acquisition of XPD Media, Zynga launched a Chinese version of "Texas Poker" -- Facebook's third-most popular game.

Both Tian and Playfish's Mo acknowledged the Chinese market's importance, but declined to say whether they were developing games for it. Both are hiring in China.

"We are still taking a wait-and-see approach for the Chinese market -- it will take time for it to fully open up," Tian told AFP

In contrast to independent studios, Chinese online game giants like Tencent and Shanda do not yet have a significant presence on Facebook, though many of its popular games have been cloned for their platforms.

Tencent, whose instant message service has more than 600 million accounts, has launched open.qq.com, its own platform for third-party developers to create games and other applications.

However, some argue conglomerates like Tencent lack the kind of fair playing field that Facebook offers because they are likely to promote their own game units.

"If you also do your own games, then you will want to push your own games... That may not be the best game for the users," Arthur Chow, chief operating officer of Hong Kong social game developer and publisher 6 Waves, told AFP.

Chow also noted Chinese studios on Facebook need to adopt a more international style, for example, by promoting virtual goods linked to Thanksgiving or Boxing Day.

"They (Facebook users) want some really creative and original ideas. That's where the challenges are, particularly for most Chinese developers."