A Federal Trade Commission official has outlined plans by that agency to become more aggressive in the area of antitrust challenges to corporate mergers.

Daniel C. Schwartz, Deputy Director of the FTC's Bureau of Competition said in a speech before a New York City Bar group yesterday that he was concerned with the rapid growth of large-scale mergers.

"The $300 million acquisition is no longer a rarity," Schwartz said. "So far in 1978 there have been nearly 60 mergers worth over $100 million each, compared with only 41 in all of 1977."

Schwartz indicated that the FTC would be using "some useful tools" in its scrutiny of potential mergers, including provisions of the Hart-Scott-Rodino premerger notification program, which he said "provides us with a particularly potent tool for obtaining additional information necessary for us to determine whether to challenge a merger."

He said the FTC would also be more often seeking injunctive relief "to prevent consummation of a merger or otherwise maintain the status quo during proceedings challenging the legality of a merger under the antitrust laws."

More importantly, though, Schwartz indicated a broadening in the agency's definition of antitrust violations to include much more than the traditional direct anticompetitive situation. Future cases will, for example, likely be brought against firms for non-economic criteria.

Schwartz said he felt antitrust cases could be made in areas of "aggregate concentration," which he called "the most far-reaching of all the approaches to conglomerate illegality.