Police seized more than 900 billion yuan ($131 billion) in cases involving underground banks last year, the Ministry of Public Security said on Sunday.

The 380 major cases involved more than 800 suspects.

The campaign against underground banks is aimed at maintaining financial order and security, and is helping the country's anti-corruption drive recover the assets of fugitive officials, the ministry said.

Last year, the ministry worked with the central bank and the State Administration of Foreign Exchange to crack down on the transfer of illicit money via offshore companies and underground banks.

Officials with the ministry said that it will continue action against illegal private banks in cooperation with the central bank and the foreign exchange regulator.

"For a long time, underground banks have become a fast channel to transfer money, for they are anonymous and hidden. Many criminals have taken advantage of the channel to transfer their illegal gains overseas," said Zhang Niannian, an official at the central bank.

Underground banks have also offered a quick way for corrupt officials to transfer their assets, Zhang added.

The central bank will track and analyze new methods of crime, especially in special nonfinancial institutions and sectors, and improve measures against money laundering, Zhang said.

Shu Jianping, head of the anti-money laundering office at the Ministry of Public Security, said that cases related to underground banks cover several industries including foreign trade and real estate.

The harm caused by underground banks is becoming a more pressing issue, Shu said, adding that local public security organs are urged to continue the campaign.