Ma Jiantang, NBS chief, last month cited incomplete data on high-income groups as the main reason for the failure to provide a national coefficient.
China had 960,000 millionaires with more than 10 million yuan ($1.58 million) in personal wealth in 2010, a rise of 9.7 percent over the previous year, the Hurun Research Institute and GroupM Knowledge reported in 2011.
Income surveys for urban and rural residents are currently carried out separately. The urban survey covers 66,000 households while the rural one covers 74,000 families.
The per capita disposable income of urban households last year was 21,810 yuan, while the per capita net income of rural households was 6,977 yuan.
The World Bank estimated that China's Gini coefficient had reached 0.47 in 2009, higher than the internationally accepted threshold of 0.4, which indicates income inequality may threaten social stability.
Yi Xianrong, a researcher with the Institute of Finance and Banking under the Chinese Academy of Social Sciences, suggested that the government introduce regulations to ensure the transparency of income information.
"The public have a right to know the Gini coefficient," Yi said.
Wu Muluan, a researcher with the City University of Hong Kong, said that more high-quality statistical data can "help enhance rational decision-making and achieve the maximum welfare of society".