WASHINGTON (AP) _ The top national security adviser for the Clinton transition team, attorney Samuel Berger, is a registered foreign agent whose firm has represented Japan and other overseas interests, according to documents filed with the Justice Department.

Berger is a partner in the law firm of Hogan and Hartson here but has been on leave since July when he became a Clinton campaign adviser. He was a State Department official in the Carter Administration from 1977 to 1980.

As a partner, Berger shares in the firm's earnings from foreign clients.

And he acknowledged Friday in a telephone interview from Little Rock, Ark., that he had done unpaid lobbying on behalf of Poland's new government and advised the provincial government of Ontario on U.S. trade law.

Berger also said he has engaged in a small amount of lobbying on Capitol Hill as a representative of a U.S. subsidiary of Toyota.

At a news conference in Little Rock on Friday where the Clinton transition team unveiled a strict new ethics code, director Warren Christopher expressed doubt that the team would include any foreign agents.

''I don't have any reason to think that there are any agents of foreign governments, and I suspect we would be very careful to screen those out of any assignments we would make,'' Christopher said.

But Berger's firm has reported to the Justice Department it is an agent for foreign clients, including the Embassy of Japan, the governments of Poland and the Bahamas, the Canadian Province of Ontario, the Council of European and Japanese National Shipowners and the automaker Daimler-Benz.

''The firm has many foreign clients, but I didn't represent'' the ones on that list, Berger said.

Berger said his lobbying on behalf of foreign clients was confined to a brief unpaid stint in 1989 on behalf of Poland's new, non-Communist government. He registered as the agent of a foreign government at that time.

Other than that, ''I've not done lobbying on behalf of any foreign government,'' Berger said.

Berger, a trade lawyer, said he has provided advice to the government of Ontario. And he said he represented a U.S. subsidiary of Toyota but insisted that it must be considered an American company.

''I'm a trade lawyer and have done a range of trade matters,'' he said.

Allen Snyder, a spokesman in Washington for Hogan and Hartson, said that Berger shares in fees paid to the firm by the foreign clients ''to the extent that any partner does.''

Berger, 47, was named by Clinton on Thursday to head transition planning on national security, one of about 50 advisers who will help redesign the government and choose policymakers for the first Democratic administration in 12 years.

Berger, who plans to return to his law firm after the transition, said he will ''comply with any restrictions that pertain to the transition.''

Under the Clinton team's new ethics code, aides must refrain for six months from lobbying in any area of the government in which they had dealings during the transition period. Top directors are banned from all lobbying for six months after the transition.

In addition, transition aides will have to sign financial disclosure reports and pledge they will not engage in any transition activity in which they, a family member or a client may have a financial interest.

All transition aides are banned permanently from using non-public information they obtained during the transition for private gain.