January 16, 2017 1054 GMT
Both demands are seen as an attempt by the authorities to prevent alarm that could trigger further declines in the yuan, the bankers from local and foreign banks said.
The yuan lost more than six percent against the dollar last year and is at eight-year lows, prompting a flurry of restrictive measures on capital outflows from the State Administration of Foreign Exchange (SAFE), including setting limits on banks' currency volumes in some cities or provinces and requiring approval for ever smaller transactions, Reuters wrote.
SAFE, which is part of the People's Bank of China (PBoC), is insisting in oral instructions to dozens of banks that they don't reveal its role in such restrictions, six bankers said. This was damaging their relationships with clients since they were unable to explain why they were turning away business.
SAFE and the PBoC have yet to respond to requests for comment.
SAFE's reticence began at least as far back as August, when its Shanghai branch called at least 20 of the major foreign and domestic banks operating in the city to a meeting with the regional heads of several SAFE departments.
A representative from an international bank attending the meeting said there were no written instructions, but a high-ranking SAFE official told them explicitly what was expected of them.
"You must control your forex deficit, but you can't say that SAFE is controlling capital outflows," the official told the bankers.
The banks were told to 'manage sentiment' to prevent public panic, the banker said, and the banks' research analysts should not broadcast any negative views on the yuan.
"They told us not to publish bad house views — analyst house views — on the yuan", the person said.
A second banker on the forex team of an international bank said his bank had received the same instructions.
Where a bank has exceeded the SAFE-set limits for forex transactions in a month, they have to turn business away, but are unable to explain the real reason why, several bankers complained.