Claim of China's economic supremacy greeted with doubt

"And this is one economic perspective. When you focus on human well-being, and the quality of growth, income inequality or environmental degradation, you would probably not enjoy that statement," he said.

The IMF's recent regional economic outlook also underscored the need for vigilance and reform.

Top 10 countries with highest GDP in 2013

Top 10 regions with highest GDP in China

The report noted that although in the past year, risks from outside Asia had receded, and action had been taken to address the vulnerabilities of Asian economies, there was still a strong need for vigilance and reform.

For China, the IMF said if the various reforms proposed by the Chinese leadership at the end of last year were fully implemented, economic growth would be cut by 0.2 percentage point this year, but by 2020 growth would be pulled up by 2.7 percentage points.

The research institute under the China Jianyin Investment Ltd, a division of China Construction Bank Corp, on Wednesday said China's potential growth will inevitably decline over the years. With an easing global monetary market, weakening domestic labor supply and tighter monetary policy, the Chinese economy has shifted from rapid growth to moderate expansion, according to the annual report of the organization.

The growth rate will slow to about 6 percent by 2030, the report said. It forecast China will overtake the US in 2027 to become the world's largest economy.

For the first quarter of this year, China's GDP rose an annual 7.4 percent, as slower property investment and exports weighed on broader growth.

"China's investment is a main driver of the economy, and the growth in the sector slowed to 17.6 percent in the first quarter," said Yang Qingwei, editor of the report and also former director of the investment bureau of the National Development and Reform Commission.

Yang said the focal point in transforming the investment landscape is stimulating private capital investment.