Eight-percent growth was no longer a problem for China's economy this year, but the real challenge was to push forward structural adjustments, a senior economist said Thursday.

Yao Jingyuan, chief economist of the National Bureau of Statistics (NBS), told a forum in Beijing that China's economy was over the worst, saying November 2008 to February 2009 was the toughest period for the economy.

The country's economy had gained momentum each quarter, which would ensure full-year growth of 8 percent, he said.

NBS data showed the economy expanded 8.9 percent year on year in the third quarter, faster than the 7.9 percent in the second quarter and 6.1 percent in the first, backed by the stimulus packages the government put into place in last November.

The stimulus packages to prop up growth had set a stage for stronger growth in the future, he said.

However problems remained, and the real challenge for the economy was to adjust its economic structure, Yao said.

"We should not pursue economic expansion in terms of size and speed in the fourth quarter or the next year, but put more efforts on structural adjustments."

He urged more efforts to boost consumption as the economic growth should rely on domestic demand. Investment accounted for about 95 percent of GDP growth, he said, without defining the exact time frame.