BEIJING -- China's retail sales is expected to top 20 trillion yuan ($3.21 trillion) this year and will grow fast on government efforts to boost domestic demand, a commerce chamber official has said.

The figure may exceed 30 trillion yuan in 2015 given an annual growth rate of 15 percent, said Zhang Zhigang, head of the China General Chamber of Commerce.

The retail sector will expand rapidly as China has adopted a long-term strategy to expand domestic demand and promote consumption, Zhang said at a forum on Friday.

China's retail sales rose 17.1 percent year-on-year to 18.4 trillion yuan in 2011, according to data from the National Bureau of Statistics.

In the first ten months of this year, retail sales increased 14.1 percent year-on-year to 16.84 trillion yuan, with the growth rate flat as that recorded during the January-September period.