The chairman of the Federal Communications Commission, disturbed over recent leaks of confidential agency documents to the press, has launched an all-out probe to determine the source of the leaks.

At the same time, Chairman Mark S. Fowler has put the agency on notice that he will move "decisively" in the future against anyone who adversely affects "the integrity of our decision-making processes."

In a memorandum sent to his fellow commissioners and high-ranking agency officials earlier this week--one that was quickly leaked to the press--Fowler complained that the commission's "ability to effectively engage in open and frank discussion among ourselves and with staff is constrained severely by these leaks. In addition, at least in some cases such premature disclosure can have signficant, adverse impact on the financial status of the companies involved."

What prompted Fowler's anger was a report in a Washington newsletter last week, Communications Daily, about an important telephone rate decision that the commission is scheduled to consider today. The newsletter, quoting from a staff document, revealed the staff's recommendation on the controversial issue.

Several commission sources have indicated that if the stock market had been open on Friday, the day the article appeared, stock prices for AT&T and its long-distance competitors could have been affected significantly.

As a result, Fowler said, "I have directed the chief, internal review and security division, to initiate an investigation" to see who leaked the confidental document. "Should an individual or individuals be found to have released this informaiton, I will institute appropriate disciplinary action."