Experts warned people to be careful when using free Wi-Fi service, after a man connected to a free Wi-Fi service was robbed of 34,000 ($5,454) online, according to www.cnr.cn.

The man surnamed Lang logged on to a bank's website and checked his account balances on his mobile phone after connecting to a free Wi-Fi network around 1 am on Feb 20.

A series of reminder messages was sent to his mobile phone over the next two hours, informing him of money being withdrawn from his savings account.

Someone withdrew 14,000 yuan in cash and transferred 20,000 yuan from his bank account to other accounts.

Li Tiejun, an engineer at the Beijing office of Kingsoft, a Zhuhai-based software company, said free Wi-Fi networks aren't very secure.

People looking to steal private information usually set up free public Wi-Fi networks to attract mobile phone users.

The public should be more alert and shut down the Wi-Fi service on their mobile phone when it's not necessary, Li said.