Business groups have once again targeted the Federal Trade Commission in a further attempt to to curb the agency's antitrust and consumer protection powers.

With the FTC's legislative lease on life due to expire at the end of September, the National Association of Manufacturers, U.S. Chamber of Commerce, American Medical Association, American Bar Association and a host of other business groups are beginning to urge Congress to put more restraints on the agency to make it harder to bring suits against unfair trade practices.

The campaign comes despite signals from FTC chairman James C. Miller III that the agency will pursue a much less activist course than the direction taken during the 1970s--in both Republican and Democratic administrations--when test cases and broad industry rules were the norm.

"Jim Miller is not going to be here forever, and neither does he have a day-to-day direction over the hundreds of lawyers in the agency who should know exactly what the intent of Congress is," said Jeffrey Joseph, manager of the business-government affairs division of the Chamber of Commerce.

How receptive Congress will be to these proposals may be known when hearings into the FTC's budget and its mission begin today. When the FTC's authority to operate expired three years ago, Congress, receptive to business pleas to curb the agency's powers, adopted limits on the FTC's ability to bring new cases.

A chief restraint proposed by business is legislation to limit the FTC's ability to issue rules and bring cases against unfair business practices. Under a recent proposal being discussed by the Chamber and NAM, suits and rules against unfair practices could be brought only if many consumers are being harmed, if the action is unavoidable by the consumer and if the benefits of the rules clearly outweigh the costs.

Business groups say this change would bar the FTC from reconsidering a proposal to ban television advertising aimed at children, which was dropped several months ago. Commission sources say it could affect the agency's crackdown on abusive debt-collection practices and retail practices such as bait-and-switch. It could also limit the types of antitrust cases the commission could bring to largely the traditional price-fixing cases, commission sources add.

Additionally, business groups are urging Congress to narrow the commission's authority to act against deceptive advertising.