WASHINGTON (AP) _ A million totem poles, arrowheads, shrunken heads and other Indian artifacts could be moving to Washington if an agreement can be worked out between the Smithsonian Institution and the Museum of the American Indian in New York.

The idea gathered force Monday as the regents of the Smithsonian resolved to explore the proposal, with the blessing of the New York museum.

''The Smithsonian Institution is not conducting a raid on another museum or municipality,'' Smithsonian Secretary Robert McC. Adams said after the regents concluded their spring meeting. ''We are anxious to see a unique collection preserved. If it is appropriate to be here in Washington, that's fine. If the solution is New York, that's fine, too.''

If Adams sounded tentative about moving the museum, Julie Kidd, chairman of board of trustees of the Museum of the American Indian, expressed ''enthusiasm for the proposed relocation of the museum to a place of national prominence in the capital, with the financial backing of the U.S. government.''

''The museum has for many years been seeking a larger, more prominent location and has explored a number of possibilities,'' Mrs. Kidd said. ''Until recently, it had sought to relocate in the former U.S. Custom House in lower Manhattan, but these efforts have been to no avail.''

The museum has had difficulty in recent years attracting visitors to its upper Manhattan location.

Mrs. Kidd said an earlier offer from billionaire H. Ross Perot of $70 million to move the museum to Texas was deferred after it looked as if they'd get the Custom House. That plan foundered on Republican New York Sen. Alfonse D'Amato's insistence that the museum merge with the American Museum of Natural History, she said.

Mrs. Kidd said the agreement with the Smithsonian was ''an agreement in principle only. The details still have to be worked out'' in negotiations. The trustees unanimously approved a resolution May 4 favoring an affiliation with the Smithsonian.

But many New Yorkers, including Attorney General Robert Abrams, who oversees foundations and legacies, oppose the museum's departure.

Abrams spokesman Timothy Gilles said Monday that one of the terms of the trust that endows the Indian museum is that it remain in New York.

Mrs. Kidd said museum officials have indicated that if the project proceeds, they will seek approval from the New York State Supreme Court for the affiliation.

Among the terms of the agreement with the Smithsonian are construction of a new facility of at least 400,000 square feet in the last vacant building spot on the Mall, between the National Air and Space Museum and the Botanic Gardens.

Currently, the museum has only about 100,000 square feet for exhibits, storage, and offices, and is able to display only a fraction of its collection.

The museum would not merge with the Smithsonian, and its board would remain intact, according to Mrs. Kidd, although Smithsonian spokeswoman Madeleine Jacobs said she could not reveal details of the proposed relationship.

Mrs. Kidd also said under the agreement, the government would pay the estimated $82.5 million for a new building for the museum, and provide another $17.6 million for conservation facilities somewhere other than on the Mall.

Also Monday, Sen. Daniel K. Inouye, D-Hawaii, said and he and Senate Majority Leader Robert Byrd, D-W. Va., would introduce legislation today to establish a National Museum of the American Indian in Washington. The museum would be part of the Smithsonian and would exhibit primarily artifacts from the Museum of the American Indian.

Under the legislation, a permanent facility would also be established for the collection in New York City.