Consolidating the nation's three bank regulatory agencies into a single super-agency would be disruptive and would do little, if anything, to improve the overall quality of regulation, representatives of those agencies testified yesterday.

Sen. William Proxmire (D-Wis.), chairman of the Senate Banking Committee, argued that the three agencies overlap and, in order to keep banks within their own regulatory spheres, have engaged in a "competition in laxity," becoming more and more permissive.

Proxmire has introduced a bill that would merge the regulatory functions of the Federal Reserve Board, the Federal Deposit Insurance Corp. and the Comptroller of the Currency into a single bank supervisory agency.

He argued that a single agency would lead to uniform standards and quicker action by agencies charged with supervising banks and forcing reforms.

He said the recent spate of revelations about Budget Director Bert Lance's dealings while he headed two Georgia banks "underscore the need for uniform action."

George A. LeMaistre, chairman of the Federal Deposit Insurance Corp., and John G. Heimann, Comptroller of the Currency, said that where a bank is controlled by a holding company, the same regulatory agency should be responsible for examining both the bank and the holding company.

LeMaistre noted that the Hamilton National Bank of Chattanooga was a sound bank, but that the mortgage affiliate of the holding company which controlled both was in difficulty.

"But for the $80 million in mortgages initiated by its Atlanta-based mortgage company affiliate, and then dumped on the bank when things went bad, the Hamilton Bank would probably be in existence today." But LeMaistre said, bank examiners were unaware of the problem that the mortgage affiliate had.

The Federal Reserve Board, under law,is entrusted with determining which activities are "closely related to banking" and may be engaged in by bank holding companies, and also regulates the bank holding companies.

But the bank (or banks) controlled by the company may be regulated by the Comptroller of the Currency, if it is a national bank, the Federal Reserve, if it is a member bank that is not a national bank, or the FDIC, if it is an insured bank that is not a member of the Fed system.

Robert Carswell, deputy secretary of the Treasury, acknowledged that the present system of three bank regulatory agencies is "cumbersome in design." He said "if you were starting it today, you wouldn't do it this way."

But, he said, the "question is where tearing it apart" will do any good.

Heimann, LeMaistre, and Federal Reserve Board governor J. Charles Partee all denied there was any competition in laxity among the three agencies.

Partee also said that stripping the Fed of its supervisory powers would make its other main function - setting monetary policy - much more difficult.

All three agency heads, as well as the Treasury's Carswell, said that there would be little gain in efficiency from combining the three agencies, that the agency would be more easily the target of industry lobbying efforts and that it would be less innovative.

The agency heads noted that since March the regulatory agencies have met monthly and have coordinated supervision standards in a number of important examination techniques.

Proxmire said he was disappointed with the testimony, that it was "self-serving."