Two Washington area men extradited from Australia last week to face charges of operating a cocaine distribution ring on Capitol Hill pleaded not guilty yesterday in U.S. District Court. They were ordered held on $500,000 bond each.

The two, Troy M. Todd Jr., 23, and Douglas W. Marshall, 27, whose arrests a year ago sparked a Justice Department inquiry into alleged drug use on Capitol Hill, arrived in Washington Sunday night after spending 10 months under assumed identities in Perth, Australia, according to court documents.

U.S. District Judge Thomas F. Hogan denied assistant U.S. Attorney Daniel J. Bernstein's request that the two be held on $1.5 million bond. In papers filed with the court, Bernstein alleged Todd and Marshall "were the focal point of a major cocaine distribution ring in this area" and that approximately 20 coconspirators have cooperated with the Justice Department investigation and are prepared to testify about the two men's involvement in the alleged ring.

Federal investigators are eager to try to talk with the two to see what information they may be able to provide on possible drug use on Capitol Hill. Marshall, a former House of Representatives page, allegedly supplied drugs to a former employe in the House doorkeeper's office, according to prosecutors' statements in court.

The employe, Robert T. Yesh, was sentenced Friday to a year in prison on charges of conspiring with Rep. Ronald V. Dellums (D-Calif.) and a Dellums aide to obtain drugs. Both Dellums and the aide have denied any wrongdoing.

Bernstein outlined in court yesterday what he called Todd and Marshall's "trickery to remain in Australia," allegedly including their use of false passports they obtained after going to a Perth graveyard and assuming the names of two young men who had recently been buried there.

Had Todd and Marshall not been arrested in January in Perth as they were attempting to leave Australia with false visas, Bernstein argued, they would never have returned to face the charges.

Christopher G. Hoge, an attorney for Marshall, and Todd's attorney, Stanley M. Dietz, requested that both men be released on personal recognizance or a bond that could be reasonably raised. Hoge argued that there was "no way on God's earth that they will be able to raise $1.5 million or $1 million or even $500,000."

Hoge accused Bernstein of going to "extreme efforts" and resorting to "character assassination" by using unsubstantiated allegations to argue in favor of a high bond.

The judge, citing the two men's "sojourn in Australia," said it "strained the credulity of the court" that Marshall was not aware of the investigation and his indictment.

There was, Hogan said, "no evidence that he Marshall was going to give himself up," and the claim by Hoge that Marshall and Todd got false visas in order to come back to the United States and turn themselves in was "not supported" by the evidence.

Hogan said the "weight of the evidence against Todd is substantial," and statements Todd allegedly made to friends indicated he "wanted to remain free, undiscovered and out of the United States."

Marshall, in a brief television interview Sunday night in Los Angeles during a layover enroute to Washington, said the entire matter has "been blown out of proportion."