Police Wednesday launched a crackdown on train ticket scalping on the Internet, as tens of thousands of students prepare to return to school for the fall semester beginning in September.

Ticket scalping was resurfacing on the Internet and public security, network supervision and railway police bureaus were cooperating in clamping down on it, the Ministry of Public Security said Wednesday.

The ministry ordered network supervision departments to monitor sales of tickets on the Internet 24 hours a day. A hotline for public complaints and information gathering has also been set up.

Tickets scalping is illegal in China. Touts do business both online and offline, so railway police should take the initiative, said the ministry.

The ministry urged an all-out effort to target gangs and wipe out scalpers, especially in areas where there were large numbers of student passengers.

"Once scalpers show up, they have to be cleaned up," the ministry said.

In recent years, reselling of tickets over the Internet via websites such as taobao.com and piao.com has flourished in China, with touts advertising for potential buyers by posting messages.

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Railway, sports match and concert tickets are the most popular items. Individual sellers dispose of their tickets because of scheduling conflicts, but scalpers regularly trade for profit at considerably above the ticket's face value.

The supply of railway tickets in China often fails to meet demand because of the country's large population, and scalpers take advantage to earn big money. Every year during the Spring Festival exodus, many people cannot obtain tickets from authorized outlets and are forced to buy from scalpers at high prices.