As the US economic recovery picks up pace, there is growing concern among China and other emerging markets about a negative impact from the upcoming winding down of US stimulus program.

The latest figure of 2.5 percent GDP growth during the second quarter of this year, which is more than double the rate in the first quarter, and the improving unemployment figures have further fueled speculation that the Federal Reserve may announce a scaling back of its monthly $85 billion bond-buying program in mid September.

Zhu Guangyao, China's vice-minister of finance, and Yi Gang, deputy governor of the People's Bank of China, the central bank, warned on Tuesday that the Fed should consider when and how fast it unwinds its economic stimulus to avoid harming emerging markets, despite the fact that the impact on China could be much less compared with some other emerging economies.

Emerging economies such as Brazil and Indonesia have been struggling with capital flight as US interest rates rise amid expectation of a winding down of the Fed stimulus program.

"The US economy is showing some positive signs and is recovering gradually and we welcome this," Zhu told a briefing ahead of the G20 summit in St Petersburg, Russia on Sept 5 and 6.

As China's economy slows down largely due to a new emphasis on domestic consumption, Zhu said China would keep economic policies stable, despite the fact that it faced a severe economic environment at home and abroad.

China has decided not to introduce a new stimulus program as a way to achieve 7.5 percent GDP growth this year, a low target in China's decades of rapid growth.

Experts believe the concern by China and other emerging markets about the Fed's tapering of its stimulus program will be a key topic at the G20.

Matthew Goodman, an economist at the Center for Strategic and International Studies, said that while emerging markets are going to talk about the financial market volatility caused by the Fed's policy, advanced countries will push back, saying that those reactions in the markets are a natural consequence of strategies by the advanced countries to keep the economies growing and these policies will inevitably have to end.

"They will also argue that a lot of the problems in the emerging markets are homegrown," he said, naming India and Brazil.

Goodman pointed out that there is no consensus in the G20 about the cause and solution of the crisis.

Eswar Prasad, a professor of international economics and trade policy at Cornell University and a senior fellow at the Brookings Institution, said the big issue right now is there has been a substantial shift in growth momentum across the advanced and emerging market economies.

"The emerging market economies are looking somewhat weaker, relatively speaking, and the advanced economies are looking somewhat more stable, relatively speaking," said Prasad, a former head of the International Monetary Fund in China.

He pointed out that these are relative because in both the short term and long term, emerging markets still have better growth prospects.

In Prasad's view, emerging markets are different and countries like China, although slowing down, continue to remain relatively stable in terms of their growth patterns, while countries like India, Indonesia and Turkey look a lot more volatile.

He said that the shifting momentum has created a different dynamic leading up to the G20 summit.

David Dollar, a senior fellow at the Brookings Institution, suggested that the US could pursue structural reforms to provide a sounder foundation for its growth, citing much-needed infrastructural construction and immigration reform.

"One issue is there are a lot of needs to repair and rebuild infrastructure in the United States. And you know, this is something the Chinese bring up a lot, that they see there's potential for more infrastructure investment in the US," said Dollar, who served as the World Bank's country director for China and Mongolia in Beijing.

Dollar is also looking forward to the reform measures to be rolled out at the Chinese Communist Party plenum in the fall.

He said if China and the US pursue their complementary reforms, it will not only help their sustainable growth, but also be a very good foundation for the world economy.

Agencies contributed to this story.