TABA, Israeli-held Sinai (AP) _ U.S. troops today entered the disputed border resort of Taba to staff a new observation post in accordance with an Israeli-Egyptian agreement.

The post on the shores of the Red Sea was inaugurated by representatives of Israel, Egypt and the Multinational Force and Observers, a 10-country organization which monitors the 1979 Israel-Egypt peace treaty in the Sinai desert.

The presence of the peacekeepers at the beach resort is largely symbolic, showing that neither Egypt nor Israel accepts the other's claims to sovereignty. International arbiters have begun hearings in Geneva to resolve the dispute.

The post, surrounded by barbed wire, consists of an observation tower and a building, both painted white. It will be permanently staffed by 10 soldiers of the 101st Airborne Division.

The tower, located on a hilltop and equipped with high-powered binoculars, provides the Americans with a view of an Egyptian border checkpoint and a palm-lined Israeli-held beach frequented by nude bathers.

During a short ceremony, multinational force commander Lt. Gen. Egil J. Ingebrigtsen of Norway cut a ribbon at the entrance to the base. He was accompanied by Egypt's Maj. Gen. Farouk Labib and Israel's Brig. Gen. Oren Shahor.

The U.S. Army said in a statement issued in Washington that the observation post in Taba was ''an important part of the parties' agreement. The parties have agreed there will be no Egyptian or Israeli military personnel in Taba.''

The Americans were selected for duty at Taba because the beach area is adjacent to the sector monitored by the United States, the Army said.

The decision to open the post was included in the agreement reached last year by Egypt and Israel to submit the 250-acre beach to international arbitration.

The beach enclave was captured by Israel with the rest of the Sinai peninsula during the 1967 Middle East war. When Israel returned Sinai to Egypt in 1982 it retained Taba, claiming sovereignty according to 1906 maps.

Egypt also claimed the Taba area, and the two countries agreed to submit their dispute to a five-member panel of arbitrators which includes jurists from France, Sweden and Switzerland as well as representatives of Israel and Egypt.

A final ruling is expected in 1988.

An Israeli government official said Israeli policemen will remain in the Taba area alongside the multinational force. ''Israel remains responsible for security in the area; the police were there before and will remain there,'' he said.

The move brings no change in territorial status of the area, the official said.