Media giant Fox is celebrating after joining fellow majors by producing its first film in Mandarin, as it battles for a slice of an exploding Chinese movie market.

The Fox International division was created in 2008 to "make local films all over the world, and to focus on markets that were growing, or that already have big established local products," said its head Sanford Panitch.

"And China being the fastest-growing market in the world, and 50 percent of the product in China being local, it was a great opportunity for us to be able to participate in making Chinese film," he told AFP.

Fox is not the first to test the Chinese movie waters -- Warner started in 2004, and has been followed by Sony and Disney, which is developing a Chinese version of its teen megahit "High School Musical."

The Fox division is already active in 10 countries: China, Brazil, France, Germany, India, Italy, Japan, Mexico, South Korea and Spain.

But it only produced its first Mandarin-language film, "Hot Summer Days," this year.

The movie, which opened in China in February and tells the stories of a series of young Chinese couples in three towns during one hot summer, made 20 million dollars in China,

"For our first Chinese movie it was an extraordinary success," said Panitch.

Stanley Rosen, a professor at the University of Southern California's East Asian Studies Center, said the highest-earning films of all time in China have all come out in the last two years.

They are led by James Cameron's global blockbuster "Avatar," which took nearly 200 million dollars in China, followed by Chinese film "Aftershock" and American movies "2012" and "Transformers 2".

"The main thing the studios are interested in, I would say, is the market inside China, with American movies," he added, noting that the number of movie theaters in China is exploding, with 1,000 new ones opening this year alone.

But a major problem is that China only allows 20 foreign films to be distributed in China per year.

This has led to the production of Chinese-language movies by the US majors -- or bilingual English-Chinese productions which are geared to both western and Chinese audiences.

While films like "High School Musical" and "Hot Summer Days" were never going to run into trouble with Chinese censors, that cannot always be taken for granted.

World War II movie "Shanghai" had problems this year with its portrayal of Japanese characters "because they were too sympathetic, which is something the (Chinese) government didn't like," said Rosen.

"So they had to make a number of changes," he added.

Fox International has already made its second Chinese-language movie: "The butcher, the chef and the swordsman," which is due out in China in November. A third is due to begin filming at the start of 2011.

"It's a competitive market because there are a lot of Chinese producers and local Chinese studios making Chinese films," said Rosen.

"So it's very active, but the good news is that China is so large that it has the ability to be able to accomodate everyone," he added.

For Panitch, China also offers another kind of opportunity.

"The exciting thing for us in China is working with new talents. We are making a point working with up and coming directors," he said.

"Part of the opportunity for us is finding the next Ang Lee or the next Stephen Chow or the next great filmmaker that we may meet making a Chinese language film, but then we could ultimately have him make a Hollywood film."