Facebook has opened a Hong Kong office as it looks to boost its presence in Asia.

The move comes despite the fact that the social-networking giant is not active on the Chinese mainland, a potentially huge market.

The sales office in Hong Kong follows on from the opening of an office in Singapore last year, as social-networking sites and Internet traffic see a marked rise in the region.

In March, the California-based group announced a new office in the southern Indian IT hub of Hyderabad to deal with advertising and customer support.

The Hong Kong opening, "following Singapore demonstrates Facebook's commitment to Asia, and in particular to Hong Kong and Taiwan, where there are active online populations and sophisticated digital marketing communities", Facebook said in a statement on Tuesday.

The company, which already has a network of sales offices in North America and Europe, said more than 80 of the top 100 advertisers in the United States advertise on Facebook, adding that it is working with major brands across Asia.

"We are investing in a team to scale with the business here in the region, and will start with a handful of employees and add more as the business grows," a spokeswoman said.

She declined to disclose the number of Facebook users in Hong Kong and Taiwan. The site has about 500 million users worldwide.

Blake Chandlee, Facebook's vice-president and commercial director for emerging markets, played down the idea that the Hong Kong office is a sign that Facebook is eyeing a move into the Chinese mainland.

"We have no plans right now to talk about entering the Chinese mainland and trying to be aggressive in that," he told AFP.

Chandlee said the site was available in "all the Chinese dialects" and "for us that is the first step in any part of the world to make sure people are able to experience Facebook in a language they're comfortable with".