WASHINGTON — Supporters of a change in federal law that would expand the claims of American Indian tribes and Native Hawaiian groups to ancient burial remains and cultural artifacts have found an unlikely foe: the Bush administration.

The Interior Department, which had supported the idea in another court case, reversed its position yesterday, saying it did not support the change, which awaits action by the full Senate.

The change in the law that protects native gravesites would allow indigenous groups to claim ancient artifacts even if the materials have no connection to any tribal group still in existence.

"In the situation where remains are not significantly related to any existing tribe, people or culture, they should be available for appropriate scientific analysis," said Paul Hoffman, a deputy assistant secretary at the Interior Department. "The proposed legislation would shift away from this balance."

Hoffman said the agency believes the law should protect the sensibilities of current tribes while balancing the need to learn about past cultures and customs.

The agency's new position gave pause to the chairman and to the top Democrat on the Senate Indian Affairs Committee, which conducted a hearing on the issue.

"They (Interior Department) were clearly in favor," said Sen. John McCain, R-Ariz., the committee chairman. "I don't think it was adequately explained why they shifted position."

McCain and Sen. Byron Dorgan of North Dakota, the committee's top Democrat, said they don't know what is next for the proposed change to the 1990 Native American Graves Protection and Repatriation Act.

Fifteen years ago the law established the rights of descendants, Indian tribes and Native Hawaiian organizations to Native American human remains, funerary and sacred objects and artifacts of cultural patrimony.

The change would add two words — "or was" — to the definition of the term Native American, redefining it to be "of, or relating to, a tribe, people, or culture that is or was indigenous to the United States." It effectively means most ancient skeletons and artifacts would be classified as Native American.

The proposed legislative change stems from a decision by the 9th U.S. Circuit Court of Appeals last year allowing scientists to study the more than 9,000-year-old skeletal remains known as Kennewick Man. Four tribes claimed the remains, found on the banks of the Columbia River outside of Kennewick, Wash.

The Interior Department decided at the time in the tribes' favor because the remains predated the arrival of Europeans to the United States. But federal courts rejected the claim, saying the remains must have a significant relationship to a presently existing tribe or culture.

Van Horn Diamond, representing his family — the Van Horn Diamond Ohana — at the hearing, said the change was needed to protect Native Hawaiians' rights to be involved in decisions relating to remains and artifacts.

"What if we find a circumstance like this (Kennewick Man) now?" he said. "Our oral tradition only takes us so far (in being able to place a claim)."

Still, some scientists and others argue that the change could potentially block future historical and anthropological study of the continent's earliest inhabitants and where they came from.

Paula A. Barran, an attorney from Portland, Ore., representing a group of scientists, teachers, students and others, told the committee that the proposed change would expand the law far beyond the boundaries of what is reasonable.

"You will have removed from the national patrimony ancient cultures and heritages that should be a source of pride for all Americans," she said. "Such actions will impoverish future generations and seriously harm education in this country."

Paul Bender, a law professor at Arizona State University College of Law, backs the change. He said a principal purpose of the law is to recognize the Indians' right to participate in decisions relating to remains and artifacts.

"These decisions have enormous and religious importance to Indian people," he said.