BEIJING, Dec. 18 -- China's exports will maintain relatively fast growth in December, but companies should remain cautious, a Chinese Ministry of Commerce spokesman said Wednesday.

Shen Danyang told a monthly press conference that an exporter confidence index rose by 1.1 percentage points from October to 100 in November, citing a ministry survey of more than 1,900 foreign trade companies.

"The index still hovers near the boom-bust line of 100, showing that trading companies are still relatively cautious about the future export situation," Shen said.

He added that the country should not be too optimistic.

Customs data showed China's exports went up 12.7 percent year on year in November, up from a growth of 5.6 percent in the previous month.

Shen attributed the fast growth mainly to the recovery in developed nations, the government's policies to stabilize expansion and a low base number in November 2012.