A high-ranking Cambodian official told three members of Congress touring Southeast Asia that his country has the remains of 80 American servicemen killed during the Vietnam war and is prepared to release them to the United States, the lawmakers said yesterday.

"Not only did they admit they had remains, but they said they were willing to give them over," said Rep. Robert C. Smith (R-N.H.), who returned Friday night from an 11-day tour of the region with Reps. John G. Rowland (R-Conn.) and Frank McCloskey (D-Ind.). The three are members of a congressional POW-MIA task force.

Smith said the only condition set by the official, Tep Henn, the Cambodian ambassador to Vietnam, was that the lawmakers or other U.S. government representatives receive the remains.

Cambodia and the United States have no diplomatic ties.

"You never know if it is going to be used as a propaganda ploy, but we felt they were sincere," Smith said. "I just want to get these remains, I.D. them and return them to their families."

Smith also said Tep Henn told the lawmakers that the Cambodians were prepared to release an American, Sterling Brian Bono of Las Animas, Colo., who was arrested in Cambodia on May 2, 1986. No reason was given for his detention.

After meeting twice with Tep Henn in Hanoi early last week, the lawmakers were planning to go to Phnom Penh to negotiate the release of the remains, but the ambassador canceled the trip, saying that Cambodian Premier Hun Sen had to be present. Hun Sen, who heads the Communist government installed by Vietnam following the invasion of Cambodia in 1978, is in Paris for a second round of peace talks with Prince Norodom Sihanouk, who leads opposition forces.

Smith called the delay minor and said the group plans to seek a meeting with Hun Sen upon his return.

Cambodian officials said some remains are readily identifiable by dog tags or other markings, Smith said.

Rowland and McCloskey said Cambodian officials told them they had remains of about 80 Americans, but Smith said he and other U.S. officials doubt the figure because it is about the number of troops the Pentagon says were lost in Cambodia.