China's Ministry of Finance is among government entities that gave informal guidance to some state-owned enterprises as recently as last month, urging them to let contracts with PwC, EY, KPMG and Deloitte expire, the report said, quoting people familiar with the matter.

While offshore subsidiaries can use the global auditors, their parent firms were urged to hire local Chinese or Hong Kong accountants when contracts come up for renewal, one of the people told Bloomberg.

The Ministry of Finance did not immediately respond to Reuters' requests for comment. PricewaterhouseCoopers (PwC) declined to comment and the other leading audit firms did not immediately respond.

Data policy is one of several areas over which China has tightened its scrutiny to try to ensure practices do not threaten the country's national and economic interests.

At the same time, geopolitical tensions are running high, with some business leaders voicing concerns about the decoupling of China, the world's second-largest economy, from the United States, the largest.

China implemented its Data Security Law in September 2021, broadly requiring Chinese companies and localities to categorize data based on its relevance to national security and the economy.

The leading accounting firms in the world by revenue are Deloitte, PwC, Ernst & Young (EY), and Klynveld Peat Marwick Goerdeler (KPMG), or the Big Four.

They collectively received revenue of 20.6 billion yuan ($2.99 billion) from all Chinese clients in 2021, Bloomberg said, quoting finance ministry data.

China has been reluctant to permit offshore authorities to access U.S.-listed Chinese companies’ audit papers without its approval, citing national security concerns.

The two sides reached a deal last year to allow U.S. securities regulators to inspect the documents in Hong Kong. The U.S. accounting watchdog in December said it has full access to inspect and investigate firms in China for the first time.

Erica Williams, chair of the U.S. Public Company Accounting Oversight Board, said on Wednesday there would be "no loopholes" for accounting firms in China that are registered with her agency.

"Should PRC authorities obstruct or otherwise fail to facilitate the PCAOB's complete access at any point in any way, the board will act immediately," she said.

($1 = 6.8951 Chinese yuan renminbi)