BEIJING (Reuters) - China's foreign exchange regulator named and shamed 10 banks that had assisted illegal capital outflows, vowing to crack down on fake forex transactions in authorities' latest effort to stabilise the sliding yuan.

The State Administration of Foreign Exchange (SAFE) listed 10 "typical" cases of misdeeds in a statement on its website on Thursday, involving money flowing overseas illegally through bank businesses such as offshore loans, trade finance, and outbound investment.

The misconduct involved local branches of 10 lenders that included some of the country's top banks, between 2017 and 2020, the regulator said.

SAFE said it will "strengthen the supervision of the forex market and crack down on illegal and unlawful behaviours with a focus on false and deceptive forex transactions."

Publishing the 10 cases is aimed at sending a warning to market players, the official Shanghai Securities News said on Friday, citing an unnamed SAFE official.

China's central bank said on Wednesday that stabilising the foreign exchange market is the top priority, and warned against one-way currency bets. The yuan has tumbled against a surging dollar over the past month.

The People's Bank of China has also asked major state-owned banks to be prepared to sell dollars in offshore markets, sources told Reuters.

SAFE will strengthen oversight of cross-border trade and investment against illegal forex transactions to safeguard national economic and financial security, the Shanghai Securities News reported on Friday.

Regulators will also closely monitor cross-border money flows, and step up the fight against fraudulent trade, the newspaper said.

(Reporting by Beijing and Shanghai newsrooms; Editing by Jamie Freed)