World of Warcraft has earned $32m for The9, the game's licensee in China, during the past three months alone. 

But uncertainty remains about the popular online game's future in China, following news that an expansion pack agreement is apparently being delayed by Warcraft developer Blizzard Entertainment while The9 upgrades servers to improve performance and user experience. 

Some 99 per cent of the China-based company's $32.2m revenue for the second quarter came from World of Warcraft, which has more than five million registered players in China.

However, analysts noted that The9 has been very successful in its efforts to license new games that are likely to be popular.

This makes The9's current reliance on Warcraft less worrying, they say, despite the firm's continuing failure to finalise a deal with US-based Blizzard for the Burning Crusade expansion pack.

"For the Burning Crusade, we are still in discussion with Blizzard regarding a launching arrangement and server arrangement, as well as details regarding the customer services," said The9 chairman and chief executive Jun Zhu.

"I believe the discussion is near to the end, and I hope it will go smoothly. Blizzard announced that Burning Crusade will be launched in the North America market early next year, so we also hope to launch this upgrade version in China as soon as possible to offer amazing additional content to the China market."

Analysts at Deutsche Bank are holding off on incorporating the Burning Crusade into their future revenue model for The9, although they believe that the two companies are still likely to agree a deal. 

With World of Warcraft's unprecedented growth in China, The9 was hit by complaints of lengthy waits to connect to the game and slow glitchy play earlier this year.

Shortly afterwards, a rift appeared between Blizzard and The9, after the US game developer announced that it was considering other operators in China for the Burning Crusade expansion.