Microsoft has accused four Chinese firms of using pirated versions of its Office software and has lodged a complaint with a government panel supervised by China's Vice Premier Wang Qishan.
According to Bloomberg, the four Chinese government-operated firms include China Railway Construction, TravelSky Technology, China Post Group and China National Petroleum (CNPC).
Last Month, the US firm alleged that 84% of its Office software deployed at China Railway Construction was pirated as well as 97% of its Windows Server client software.
Microsoft also reported that about 40% of CNPC's Office and Windows server client software was pirated while majority of Travelsky's Office software was unlicensed and 93% of China Post's come from unlicensed versions.
China Railway Construction said in the statement that the company will not rule out the possibility some subsidiary units may have used unauthorised software, but denied the figure was so high.
"The company attaches great importance to this matter, and we are holding an internal inquiry," the statement said.
According to a report, in 2011, the illegal software market in China was worth about $9bn, compared to the legal market of below $3bn.
During early 2012, Microsoft sued China's Gome Electrical Appliances and a Beijing electronics mall for supposedly violating the copyright of its software.