China's MMO gamers have taken to World of Warcraft - but the game's future in  that country is uncertain.

More than 4.3 million World of Warcraft user accounts were paid for and activated in China during the past year, according to The9 Ltd.,  which operates the game in the country.

WoW developer Blizzard, claims more than six million players worldwide. If this is true, China accounts for more than half that figure.

The9 Ltd, which operates World of Warcraft in China under licence, acknowledges that Blizzard has still not given it permission to update the game with the forthcoming Burning Crusade expansion.

Blizzard is asking for a bigger percentage of the game's profits in China. There is also concern that The9 will operate a competing online game, Guild Wars.

The9 -  which made more than $26 million from the game in the first quarter - refuses to renegotiate the terms agreed when World of Warcraft was launched in China.

Private negotiations between the two companies went public when Blizzard announced that The9 would have to negotiate for the Burning Crusade expansion, scheduled for release next year. Such expansion packs are usually part of the original game, and cannot be operated independently.