King & Wood Mallesons (KWM) is advising Microsoft as the technology giant faces a major anti-monopoly probe in mainland China.

Chinese regulator the State Administration for Industry & Commerce (SIAC) launched an investigation against the company this week, on suspicion that it had participated in anti-competitive behaviour.

In a statement on SIAC's website, it said nearly 100 enforcement officers had visited the premises of Microsoft in Beijing, Shanghai, Guangzhou and Chengdu to gather evidence.

Microsoft employees including the vice president, other senior management and those in the finance and marketing departments have all been interviewed and information seized from computers.

A KWM antitrust team in Beijing is representing Microsoft, led by senior partner and head of the international trade, antitrust and competition group in China, Susan Ning.

The firm, which has seven Beijing-based anti-trust lawyers listed on its website, was required to be present during the investigation.

In a statement Microsoft said: "Microsoft complies with the laws and regulations of every market in which we operate around the world and we have industry leading monitoring and enforcement mechanisms in place to ensure this. Our business practices in China are designed to be compliant with Chinese law."

The investigation into Microsoft comes as increasing numbers of Western companies are probed for anti-competitive or corrupt behavior.

Ropes & Gray was last year engaged by GlaxoSmithKline (GSK) in China, after Chinese officials alleged that pharmaceutical giant had engaged in bribery.