Police in Beijing are to crack down on illegal sexual activities at public places by visiting bars, nightclubs and bathing centers on the 11th of each month, the Beijing Morning Post reports.

A three-day inspection, codenamed "thunder power" that is currently in progress and will finish Friday, is the latest step in the campaign against the illegal sex trade.

An official at Beijing's public security department said their inspections would focus on 44 recreation centers with a history of allowing illegal activities and that any found to be re-offending would be ordered to suspend business, then would be permanently shut down if they were found to re-open secretly.

Police in most Chinese cities have stepped up their fight against porn-related businesses this year after indications the illegal industry was growing fast.

Beijing police raided several luxury nightclubs in May and found their barmaids to be involved in prohibited activities.