Cleaners in Tongren, Guizhou province, have been on strike since Saturday to protest the city government's refusal to pay into the social security fund for them, China National Radio reported on Monday.

One worker told the?reporter that the situation came to light when a recently retired worker found authorities had not paid any social security for them since 2007.

More than 1,000 workers went on strike.

Fu Gang, director of Tongren's urban management, said a computer error had led to the government not paying the workers' social security for two years.

About 300 cleaners have been affected, he said, adding that the government had vowed to pay into the social security fund as soon as possible.