China has launched a campaign to persuade more women to breast feed, worried that Chinese babies' development lags developed countries because they are not fed properly in their first months of life.

The government is also worried about the growing use of powdered baby milk formula -- which many Chinese believe is more "modern" and better for the baby -- especially after 13 babies died of malnutrition in 2004 from being fed fake formula.

"Breast milk is a necessary and ideal food for a baby, and the nutrients it contains are the most suitable for the baby's digestion and nourishment," the Health Ministry said on Wednesday in a statement on its Web site (www.moh.gov.cn).

"For mothers, breast feeding is beneficial to post-partum recuperation," it added, without saying what the breast-feeding rate was in China.

Chinese babies put on less weight in their first six months than babies in developed countries, the ministry said.

"The main reason is parents lack scientific knowledge about feeding," it said, adding that problems caused by poor baby nutrition might include mental retardation.

There was a particular problem in the countryside, where parents did not know when or how to best start introducing solid food to babies or how to balance their nutritional requirements, the ministry said.

The government would spend more time promoting breast feeding and providing information as well as enforcing a ban on baby milk formula being sold or advertised in hospitals, it said.

Studies around the world have shown that breast-feeding has many advantages for children including reducing infections, respiratory illnesses and diarrhea.

Other studies have shown that babies who are breast-fed for the first six months of life grow better without getting too fat.