United States-based Facebook Inc, operator of the world's largest social-networking site, said its business aiding China's exporters to reach global markets is seeing fast growth even as its main Internet services remain blocked in the nation.

Facebook also has "thousands" of application developers in China, Vice-President Vaughan Smith told the Global Mobile Internet Conference in Beijing on Tuesday.

Smith didn't comment on the outlook for offering Facebook's social network in China, where it's accessible only through proxy services that sidestep government censors.

Facebook said in the prospectus for its 2012 listing that "substantial legal and regulatory complexities" prevented its entry into China, home to the world's largest number of Internet users. That has led the company to instead focus on supplying marketing services to exporters.

"We have a rapidly growing business in China helping people that are exporting- exporters from China reaching customers around the world," Smith said. "We've got 1.3 billion people on Facebook and it turns out that marketing to those people from China works really well."

Chief Operating Officer Sheryl Sandberg in September met with the government agency that oversees controls on the Internet in China. Sandberg and Cai Mingzhao, head of the State Council Information Office, discussed issues including the "important role" that Facebook plays in helping Chinese companies expand overseas, according to a statement posted on the agency's website at the time.

Along with Facebook, most other US-based social-networking services, including Google Inc's YouTube and that of Twitter Inc, are also blocked in China. That leaves LinkedIn Corp, which set up its local professional networking site in Chinese in February, as the biggest US social media company active in China.

Without entering China, LinkedIn couldn't accomplish its corporate vision, Derek Shen, the company's president for China, said Tuesday.

"We have to accomplish our global mission to connect all professionals across the world," Shen said. "China has a lot of excellent professionals but they don't have a good global platform."

China has room for more social networks and there is nothing to stop companies from the US or elsewhere from entering, Weibo Corp Chief Executive Officer Wang Gaofei told the conference. Weibo, China's most popular micro blog service, was spun off by Sina Corp last month in an initial public offering.

"The market is open - no matter whether it's Sina, Tencent, LinkedIn, Twitter or Facebook, they can all do it," Wang said. "With the increasing number of mobile Internet users, users' demand will become more specific, which will lead to a more diversified social networking market."

Tencent Holdings Ltd operates the WeChat messaging service.