The Senate Commerce Committee will take up legislation today that if passed, could cast serious doubt about the Federal Trade Commission's future authority to require health warnings in cigarette advertisements.

Several Federal Trade Commission officials expressed concern yesterday that the legislation, sponsored by Sen. Robert Kasten (R-Wis.), chairman of the Commerce consumer subcommittee, may make it much more difficult--and perhaps impossible--for the commission to continue to regulate the cigarette manufacturers' advertisements.

"I think the legislation will throw our ability to regulate cigarette advertising into some confusion," said FTC Commissioner Patricia Bailey. "It will make it extremely difficult to deal with various ramifications of cigarette advertisements," she added.

The legislation would, among other things, bar the commission from regulating any unfair advertisements. The legislation, which authorizes the consumer protection agency for another three years, also would drastically curb the agency's authority to regulate doctors, dentists and other professionals.

Strongly supported by the advertising industry, the ban on unfair ads in effect would bar the commission permanently from banning television advertisements aimed at children. Commission sources also said the prohibition could bar the commission from cracking down on ads that encourage unsafe practices among children, such as ads that show children drying their hair with a blow-dryer over a sink full of water.

Jack Mills, senior vice president of the Tobacco Institute, said that the industry favors eliminating the FTC's unfairness authority. "It is so broad a term that anybody can think an ad is unfair," Miller said. However, he added, "We're not involved in lobbying in this in any way at all."

Nonetheless, one commission official, expresssing the concerns of several others, charged that eliminating authority over unfair advertisements is really an attempt to "get the FTC out of the tobacco business."

Although Congress specifically has mandated warning labels on cigarette packages, it is the FTC that ordered the same labels be attached to cigarette advertisements under a consent order reached with the tobacco industry in the early 1970s.

Some commisison officials and congressional aides fear that any change in the FTC's authority to attack unfair ads would lead the cigarette manufacturers to seek the repeal of that consent order.