The Federal Trade Commission yesterday accused the manufacturer of Amana microwave ovens of deceptive, misleading and unfair advertising by promoting its product as the only brand to pass all safety tests when the company knew one other brand also passed the tests.

In the first deceptive-advertising complaint brought by the agency since Reagan appointee James C. Miller III assumed the FTC chairmanship, the commission unanimously concluded that Amana Refrigeration Inc. also misled consumers when it advertised that owners of other brands of microwave ovens rated Amana as "best quality."

According to the FTC complaint, "The vast majority of owners of other brands of ovens did not rate Amana 'best quality.' "

The commission charged that Amana -- a leading maker of microwave ovens -- falsely claimed that Amana made the only one of six major brands that passed rigorous safety tests. The commission said that, in making that claim, Amana knew that a seventh brand -- Panasonic -- also passed the safety tests but knowingly worded its ads to avoid noting that fact.

If the FTC's charges are found to be true after an extensive hearing, the commission could bar the Iowa-based appliance maker from making similar claims in the future unless the claims were sufficiently supported by back-up data.

Amana said it would contest the complaint. "Our ads are true . . . the ads do not mislead any consumer. The assertions made in the ads are supported and substantiated by data which was developed prior to the dissemination of the ad," the company said.

What's more, the company noted, the ads in question were stopped nearly two years ago.

"We believe in this case the FTC is wrong in going after this campaign that ran two years ago and is spending its efforts on things that are not in the public interest. It is wasting resources that should be directed at new issues that make sense," the company said.

Amana lawyers complained that the FTC complaint runs counter to recent positions on advertising made by Miller and his director of the Bureau of Consumer Protection, Timothy Muris.

In congressional testimony and frequent speeches, both Miller and Muris have argued that the commission's powers to attack deceptive advertisements should be curbed to the point that the agency could bring complaints only after the commission could clearly prove, through scientific studies, that the ads were misleading and that consumers were harmed by these false claims.

Muris, however, disagreed with Amana's arguments and urged the commission to issue the complaint -- with Miller's backing.

"This is clearly a good case," Muris said, arguing that Amana's quality and safety claims were important in influencing consumer decisions and that, if consumers made their decisions on false claims, then they were injured.

"We have never suggested that a valid survey and a rigorous cost-benefit test be applied to each and every complaint," Muris said in defending the complaint.

Muris has been under fire from several congressmen for bringing less than a handful of consumer-protection complaints during Miller's year in office. He noted yesterday that this complaint is the first of several about to emerge from the commission in the next few months.