The China Banking Regulatory Commission is confident about the authenticity of non-performing loans data it has released, a senior official with the regulator said on Friday.

Wang Junshou, deputy director of the commission's general office, admitted there had been flaws in the data in early years, but the quality of the information now had improved greatly from when the regulator was set up in 2003.

Non-performing loans at China's banks rose by an additional 54.1 billion yuan ($8.66 billion) to 646.1 billion yuan in the three months to March, according to data from the commission released on May 15.