The art dealers of America are up in arms. The House Ways and Means Committee is actively considering a law aimed at curbing the international traffic in pillaged and stolen art treasures.

"I couldn't believe it," Rep. Abner J. Mikva (D-Ill.) said of opposition to the bill he naively introduced less than two months ago. "It was just amazing to hear the arguments. The gist of them was, 'We've got to pillage, because if we don't, someone else will.'"

Members of the American Association of Dealers in Ancient, Oriental and Primitive Art maintain that this is a crassly unfair way of describing their complaints. HR 5643, as even Mikva admits, is far from perfect.

The protests, however, suggest that not a few dealers and collectors alike would have to be a great deal fussier about the origins of the "cultural property" that comes their way. In addition to stolen museum pieces, the bill would cover archaeological and ethnological items subject to frequent pillaging. According to one scholarly estimate, between 75 and 95 per cent of the archaeological collections in the nation's most prestigious museums would never have gotten there if the standards proposed by HR 5643 had been in force.

Basically the bill would implement a 1970 United Nations Educational, Scientific and Cultural Organization convention designed to combat the increasing illegal trade in national art treasures that has led to wholesale Pillaging in some countries. Thirty nations, such as Mexico, Ecuador, Nepal and Zaire, have joined the agreement, but the United States would be the first major art-importing country to carry it out.

That prospect has ancient, primitive and oriental art dealers from New York to San Francisco anxiously wringing their hands and suggesting that thee United States is headed for a cultural doomsday while the rest of the art world laughs.

"With the passage of this law, the entire flow of art will be to the European collecting countries, Japan and the Arab oil states," Edward H. Merrin, a Fifth Avenue dealer in ancient art, told the House Ways and Means Trade Subcommittee at a recent hearing. Illegal digging in the Third World countries that have signed the UNESCO convention would increase, he predicted, to make up for the loss of the top dollar Americans pay.

"Should the price of an object be cut in half," he warned, "the nationals of these countries will have to dig twice a much to get the same money. After all, these excavations are done by the poor whose regular income is not enough to feed a family, and they must get extra money somewhere."

The Senate unanimously voted in 1972 to ratify the UNESCO convention but Congress has yet to adopt the requisite implementing legislation. Mikva's bill, a combination of State Department proposals and refinements by the staff of the House Trade Subcommittee, is the third major draft in the effort.

The measure would prohibit the importation into the United States of objects stolen from museums or religious or public monuments of another country and would set up procedures for their seizure and return.

Other more sweeping and controversial provisions are aimed at frequently pillaged "archaeological or ethnological" materials. The President, acting on the advice of a panel of experts, would be empowered to enter into individual agreements with endangered UNESCO convention nations. The agreements would sharply restrict the imporation into the United States of listed artifacts. The U.S. Customs Bureau would serve as the enforcer, empowered to demand "satisfactory evidence" of compliance with the complicated law being proposed.

Douglas C. Ewing, president of the dealers' association, asserted in his testimony that the law would be "a cultural disater to the United States" without materially helping to reduce the pillage of foreign lands.

Miami art dealer Lee Moore put it even more bluntly, contending that the treasure left behind by ancient and primitive civilizations belongs to everyone. He said it ought not "be considered solely the property of a few that now occupy the land of these aboriginal cultures who claim it categorically as 'National Patrimony,' which they do little or nothing to preserve and share with the world."

New York art dealer Peter Marks added in a telephone interview: "If HR 5643 had been law 100 years ago, there wouldn't be a single museum in the United States - except for those devoted to American Painting, American furniture and American art. That's fine, but America, after all, is a melting pot. We have people who want to understand their 'Roots,' if you will.

Representing most of the major art dealers in the country, the association was formed several years ago, Marks said, "precisely in response to the legislation now pending." Its Washington lawyers, from the firm of Arnold & Porter, are pressing for "substantial surgery" on the bill. Meanwhile, the dealers and their art-collecting friends have mounted a select, but vocal, lobying effort.

Subcommittee Chairman Charles A. Vanik (D-Ohio) has gotten dozens of protesting letters and telegrams. More complaints were heard last week at a subcommittee markup session that Vanik opened up for "additional remarks" from interested parties.

Mikva said he's been contacted repeatedly by art collectors and their friends. One telegram he got from a Fifth Avenue address left him flabbergasted. It warned:

"If HR 5643 is passed, it will be your responsibility to tell the black family with five children that if they want to see African art, all they have to do is spend $7,000 or $8,000 and fly to Africa just like the white people do in suburban Chicago. You can also add that the following year, for several thousand dollars more, they can go to Greece."

Despite such opposition, the State Department has come out strongly in favor of the bill while suggesting some amendments, such as one permitting U.S. agreements with art-importing countries outside the UNESCO framework. The Association of Art Museum Directors has taken a similar tack.

Extensive worldwide traffic in archaeological and ethnological treasures has led to "widespread depradations in some countries . . .the destruction of ceremonial centers and archaeological complexes of ancient civilizations and . . .the removal of stone sculptures and reliefs," Assistant Secretary of State Joseph D. Duffey informed the subcommittee. "In addition, the theft of art objects from museums, churches and collections has been increasing."

The endorsements by the big museums, such as the Metropolitan Museum of Art in New York, have been met with a certain skepticism. Michael D. Coe, curator of anthropology at Yale's Peabody Museum of Natural History, said the older, large museums "with their huge collections and exhibits" can afford to be enthusiastic about the treaty as distinct from the "have-not" museums scattered about the country.

Mikva agreed that "it is easier for the large, well-established museums to be statesman like about this," but thinks that "you still can't condone pillage" on behalf of the others.

No date has been set for the next markup of the bill, but Mikva appears ready to make some substantive changes to improve the measure.

"There is going to be an effort ot sharpen the language and make it more precise," he said. "The proposal didn't come down from Mt. Sinai."

But he disputed the notion that none of the other importing nations would follow suit. As one witness pointed out, Mikva said, "when America set standards on endangered species like the whale, Japan and Russia didn't follow suit, but the action still slowed down the extinctin rate and it has put pressure on the other countries."

What really exasperates Mikva is the persisitent theme that the poor nations aren't capable of protecting their art for the enjoyment of the rest of the world.

"It's kind of 'white man's burden,'" he said of the theme. "It just drove me up the wall. It's really the same argument that's been used with bribery: 'All the other nations are doing it, so we have to do it, too.'"

Mikva said he doesn't buy that. "We're either a moral nation or we're not," he said.