The chairman of the Federal Home Loan Bank Board said today that the only short-term cure for the nation's ailing savings and loan industry is lowering interest rates.

The official, Richard T. Pratt, addressing the annual meeting of the Federal Home Loan Bank of New York and a subsequent press conference, did, however, announce that his agency will propose regulations next week that will make it easier and quicker for savings and loan associations to issue stock.

Pratt, however, admitted that the action, while in line with his general deregulation views, holds little hope of providing the short-term relief that thrift industry officials have been seeking in Washington.

"The only solution that will get this business back on its feet," Pratt told reporters, is the lessening of interest rates. "In my opinion, that is the item that should be focused on above all others."

Speaking to more than 1,000 savings and loan officials, Pratt said the industry never again will operate in a heavily regulated, less competitive world such as existed before the erosion of the industry's savings base to new ventures, such as money market funds. The industry "cannot return to a highly regulated, protected world" of the past, Pratt said.

Rejecting broad, multibillion-dollar bail-out schemes proposed by some savings and loan industry officials, Pratt said the "time may be appropriate" to expand the powers of S&Ls to offer certificates or other instruments, like money market funds, tied to floating interest rates.

He did note that he could support bail-out plans that would "minimize impact on the federal budget" and also would be only a "temporary source" of federal funds. Such a plan, he added, would serve only as a "bridge to provide transition" for the troubled industry.

"I don't want to have to regulate your salary, whether you belong to the country club or what you pay your directors," Pratt said, warning of regulatory plans that could make S&Ls like the "branch post office."

Despite pleas from S&L leaders, neither the Reagan administration nor Congress has come up with concrete plans to aid the industry, which lost a record $3.1 billion during the second half of 1981.

For the entire year, federally insured S&Ls lost $4.6 billion, a figure that is expected to climb substantially this year, and in recent weeks several federally engineered mergers have saved a cluster of troubled associations.

Pratt's view has consistently been that the industry must be given the authority to, in effect, revive itself, and the board has issued a series of rulings designed to widen the powers of the individual institutions.

Announcement of the proposed stock-issuing rules is a similar plan. Pratt said he wants to give the industry "tools for survival as rapidly as we can."

The rules, when issued next Wednesday, are expected to ease the timing and paperwork for converting mutual S&Ls into stock-owned institutions, a move designed to encourage flexibility and prompt investment. The regulations apparently would permit S&Ls to adopt "shelf registration" plans, permitting stock offerings to hit the public market when conditions permit.