BEIJING, Jan. 15 (Xinhua) -- A Chinese official has said the country's family planning policy should be unswervingly adhered to.

The policy should be a long-term one and its primary goal is to keep a low birthrate, said Wang Xia, minister in charge of the National Population and Family Planning Commission, at a national conference on Monday.

The authorities will expand pre-pregnancy check services to reach all county-level areas across the country and ensure migrants' equal access to related public services this year, according to Wang.

At present, such services are available in about 60 percent of county-level areas, covering more than 80 percent of the target population, according to the official.

Efforts should also be made to rectify the imbalance in gender ratio, she said.

Wang added that the birthrate in China was held at a low level in 2012.