China's political leadership is considering ending the country's hated "one-child" policy because it is damaging the economy and creating a demographic timebomb, a senior minister admitted today.

Zhao Baige, Vice Minister of the National Population and Family Planning Commission, revealed that there is concern at the highest levels that the policy is already tearing apart the fabric of society.

"This has become a big issue among decision makers," Ms Zhao told reporters at a routine government press conference in Beijing.

"We want incrementally to have this change. I cannot answer at what time or how."

China imposed the one-child policy in 1979 to curb population growth that had rocketed out of control since Mao Zedong's instruction to the nation in the 1960s to bury the United States in a human wave.

After Mao's death a network of rules was imposed on families – more complex than the simple instruction not to have more than one baby – although parents who comply with this rule still receive a certificate and a lump sum on retirement.

Two babies were permitted in many areas in the countryside, or if the first child was a female, since Chinese tradition strongly favours sons.

Fines were imposed for rule-breakers, and state officials who have more than one child automatically lose their jobs.

The rules are privately detested by most Chinese, and have been criticised abroad. Human rights activists complain that the one-child policy has led to the practice of eugenics, and that the Chinese state uses it as a method of social engineering.

Ms Zhao indicated that there are no plans do away with family-planning policies altogether, as in the short term China's 1.3 billion population is still growing.

State media said in December that numbers would reach 1.5 billion people by 2033, with birth rates set to soar over the next five years.

There is also official concern that the family planning rules are too often being flouted. Officials acknowledge that population controls are being unravelled by the increased mobility of China's 150 million-odd migrant workers, who travel from poor rural areas to work in more affluent eastern cities.

China has vowed to slap heavier fines on wealthy citizens who break the rules in response to the emergence of an upper class willing to pay standard fines to have more children.

Nonetheless, Ms Zhao suggested that long-term planning on how to bring the policy to at least a partial close may already have begun.

"The attitude is to do the studies, to consider it responsibly and to set it up systematically," he said.

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