Federal Reserve Board Chairman G. William Miller has told the chairmen of the House and Senate banking committees that he would not pay member banks interest on the accounts they keep at the Federal Reserve without congressional assent.

Miller said in a letter that he believes the Fed has the authority to do so without explicit legislation but that, if the committees disagree, "It would seem to be unlikely that the board would undertake payment of interest on reserve balances in the absence of appropriate congressional approval."

Miller wants to pay member banks interest on the deposits they are required to keep with the central bank to stop the flight of banks from the Fed system.

Banking committee chairman Sen. William Proxmire and Rep. Henry Reuss, both Wisconsin Democrats, wrote Miller last week that they did not believe he had the authority to pay interest on member banks reserves without authorizing legislation, and they warned him against doing so.

The Fed earns about $7 billion a year in interest on the government securities it owns for trading in its open market monetary policy operations. After it pays its expenses (which last year totalled $5.9 billion), the Fed returns the rest of the interest to the Treasury.

Reuss and Proxmire said they feared that the Fed would become a $7 billion spending agency if it started paying interest on member bank deposits without congressional legislation.

The Treasury has proposed a bill that would permit the Fed to pay interest from its securities income to member banks in order to make membership in the central bank more palatable.

After World War II, Fed member banks accounted for about 85 percent. The Fed worries that, as more and more banks drop membership (46 did in 1976 and 45 did in the first six months of 1977), it will be harder to conduct an effective monetary policy.

Miller told Reuss and Proxmire that he is developing a program to keep banks in the Fed system that might include revisions in reserve requirements, some earnings on deposits, and charging banks for services that the Fed now renders free.