China will intensify a crackdown on illegal fund-raising activities after an increase in such practices last year, a senior legal official said on Monday.

Chinese public security departments cracked 3,700 illegal fund-raising cases in 2013, said Liu Zhangjun, director-general of the Office of the Inter-agency Anti-illegal Fund-raising Taskforce, at a press conference in Beijing.

The office said authorities had helped investors recover more than 6.4 billion yuan (1.04 billion U.S. dollars) of lenders' losses last year, the official said.

"Currently we are faced with severe challenges. The numbers of illegal fund-raising cases, total funds raised and those involved remain at high levels," the official said.

He said illegal fund-raising comes in different forms, such as by offering false wealth management products, valueless commemorative coins, stamps and currency notes, as well as the sale of sham stocks by self-claimed private banks to investors.

Meanwhile, online peer-to-peer (P2P) business has also become a risky area where illegal fund-raising occurred, along with the rising fashion of Internet finance in the country, Liu said.

Authorities will enhance crackdown efforts against fraudulent advertisements while educating the public on risks, Liu said.