Justice Department lawyers, at the urging of nations troubled by a hemorrhage of their art into American collections, are investigating several art dealers, including a New York importer who attempted to bring $1 million worth of Peruvian artifacts through Dulles International Airport.

Federal prosecutors refused yesterday to comment on the investigation, now before a grand jury in Alexandria, but others familiar with the case said it could evolve into a test of the government's ability to use stolen property laws to regulate the importation of foreign artifacts. Under that theory the government contends that the artifacts have been "stolen" from countries that have laws asserting ownership over all antiquities.

The Alexandria investigation grows out of the seizure Jan. 16 by customs agents of gold, silver and pottery objects from a Braniff plane that landed at Dulles after a nonstop flight from Lima.

A source familiar with the probe said indictments in the probe are expected early next week.

Customs officials and museum experts said yesterday the case represents a significant development in government attempts to crack down on the flourishing trade among U.S. art dealers and collectors in valuable pre-Columbian objects from Latin American countries.

At the same time, Customs authorities concede that efforts to tighten import restrictions are raising a legal thicket over ownership and possible criminal prosecutions in cases where artifacts may have been purchased legitimately and without knowledge of the "stolen property" question.

Douglas Ewing, president of a 60-member dealers association in New York, yesterday sharply criticized the Customs probe, saying the agency seems "to be trying to do by regulation what Congress for nine years has refused to do." Ewing said that although a 1972 United Nations treaty regulating trade of artifacts was signed by the United States, Congress never has passed implementing legislation.

Law enforcement officials yesterday declined to give details about the objects seized at Dulles, but Clemency Coggins, a research associate at Harvard's Peabody Museum, said such pieces typically include carved jade, ceramic vessels and small stone masks.

The items already have acquired a small legend. Clifford Evans, a 60-year-old Smithsonian Institution archeologist who viewed the crates seized by Customs, suffered a heart attack shortly after returning to his office on Jan. 19 and died a few hours later at George Washington University Hospital.

Evans, Coggins and other museum officials and academicians have campaigned for years for stricter laws governing the worldwide trade in antiquities dug or cut from Mayan and other Latin American ruins.

"The Conquistadors in the 16th century leased rights . . . to mine these ancient sites for gold," Coggins said yesterday. "You'd think Peru would be empty by now, but they keep finding new ones."

"It's a bad situation," agreed Frederick J. Truslow, a Washington lawyer hired to represent the government of Peru in the matter. "You don't have Indiana Jones going down there. But you have a fellow who'll dig up a pot knowing he can get 50 bucks for it, and it completely destroys the archeological context."

The items at Dulles were impounded after customs agents held that they were undervalued. Agents reportedly then raided the dealer's New York apartment and found hundreds more objects, which led to the criminal investigation.

A 1972 law passed by Congress served to choke off much of the trade in large, so-called monumental art works, but smaller, portable items like those in the Dulles case have continued to enter the United States freely, several experts said yesterday.

In its efforts aimed at these items, Customs is trying to invoke the National Stolen Property Act, contending that while the objects may not have been "stolen" in the sense of theft -- and some may have been purchased legitimately -- they are subject to foreign laws strictly forbidding their export.

As a precedent, Customs attorneys cite a Texas case in which five persons were convicted of selling Mexican artifacts. The convictions were upheld by a federal appeals court in New Orleans in 1979, which ruled that Mexican law claiming ownership of the objects made their importation into the United States illegal.