WASHINGTON (AP) _ Most manufacturers of cosmetics are not signing up for voluntary federal oversight, according to a report to Congress released Monday.

A congressman who wants to increase oversight of the $18 billion industry said the report raises safety questions.

The Food and Drug Administration has no authority to require safety testing of personal-care products, which includes everything from toothpaste to bubble bath, or to force manufacturers to report safety data or cosmetics-related injuries, noted the report by the General Accounting Office, the investigating arm of Congress.

''Most people think somebody approves these products in advance ... that the government would have access to safety data, that there's a review of the chemicals (in the products), but that's not what goes on here,'' Rep. Ron Wyden, D-Ore., who requested the report, said in an interview.

Wyden is chairman of the Small Business subcommittee on regulation,

He said the Food, Drug and Cosmetic Act, on the books since 1938, needs to be rewritten to require cosmetics manufacturers to register with the FDA and provide the agency with data on safety tests and injury reports. He said he expects to introduce legislation to that effect later this year.

The Cosmetics, Toiletry and Fragrance Association defended the industry, saying: ''There isn't a serious safety problem ... If there was ... the agency would know about it and the public would know about it.''

The association, the main trade organization for the cosmetics industry, has been encouraging manufacturers to register voluntarily with the FDA and has been collecting and reviewing safety data on chemicals used in cosmetics, said Michael Petrina, the group's vice president for legislative relations.

''The FDA has plenty of information now to make any judgments to deal with any safety concerns,'' he said. ''We don't think the FDA needs any more authority to regulate ... We don't think it makes any sense to divert their scarce resources to an industry that has a demonstrated safety record.''

The GAO report said that according to FDA estimates, there are about 2,000 to 2,500 cosmetics manufacturers and about twice as many distributors.

The drug agency's records show that 778, or 31 percent to 39 percent, had registered with the agency as of July 1989, compared with about 40 percent in 1977, the report said.

The trade association says the total number of manufacturers is no more than 2,000 and the number registered is closer to 60 percent. And the group notes that the 778 registered last year was 94 more than in July 1988.

About 3 percent of the estimated 4,000 to 5,000 distributors have reported adverse effects of personal-care products to he FDA, the report said.

The FDA can inspect manufacturers, collect samples and go to court to force products off the market if it finds safety problems.

But the report noted that only companies that register with the FDA will be inspected, because otherwise the agency doesn't know they exist. Also, unless a company reports safety-testing data to the agency, their products won't be reviewed by the FDA.

''Because it is a voluntary program ... FDA will never be able to require reporting from all companies, particularly those that may be least likely to report because they have experienced problems with their cosmetics,'' the report said.

The report also said FDA officials have said their investigators have found many manufacturers lack adequate data on safety tests of their products and, unless there is a problem, refuse to disclose the results of their safety tests.

An FDA spokesman said agency officials had not yet seen the report and had no immediate comment.

Cosmetic products sold to consumers must list ingredients on the label, but that regulation does not apply to products sold for use in business establishments like beauty salons, the report said.

Wyden said he is particularly concerned that the FDA had not done its own assessments of the4 health effects of 884 chemicals available for use in cosmetics that are listed in the government's Registry of Toxic Effects of Chemical Substances.

Petrina said his association has reviewed the chemicals and found that many are not used in personal-care products. Of those that are, none poses a safety problem in the small quantities in which it used, he said.