A multinational force of 2,600 troops and observers begins patroling the eastern edge of the Sinai at midnight tonight to check whether Israel and Egypt are sticking to their peace treaty and to report violations to both sides.

The United States is providing nearly half the manpower and 60 percent of the money for the 10-nation force, which already is in place.

Unlike previous peace-keeping groups in the Middle East, the force was not set up by the United Nations. The United States persuaded the participating nations to join individually because Soviet, Arab and Third World opposition to the Camp David accords prevented the world body from playing a role.

The Israeli-Egyptian peace treaty, signed at the White House on March 26, 1979, says troops in the force will "supervise the implementation" of the treaty and "employ their best efforts to prevent any violation of its terms."

The force, with headquarters at Eitam in the northeastern Sinai, will make tours to monitor the area at least twice a month. It is to ensure that Egypt and Israel do not exceed the treaty's limitations on the level of military forces in the easternmost of three Sinai zones. It also will seek to prevent smuggling of arms from the Egyptian side to Palestinian guerrillas in the Gaza Strip and to keep the border area from becoming a staging ground for guerrilla attacks.

The force's commander, Lt. Gen. Frederik Bull-Hansen of Norway, was quoted by Reuter as saying that the troops will not engage in combat or take any action to correct violations but only "observe and report in both these countries, which have decided to solve their problems peacefully."

The group is formally called the Multinational Force and Observers, or MFO. Its members come from the United States, Colombia, Fiji, Australia, New Zealand, the Netherlands, Italy, Uruguay, France and Britain. Officials estimate its first-year cost at $225 million.

The United States is providing 1,100 soliders, including 670 paratroopers from the Rapid Deployment Force, a helicopter unit, a 300-member supply team and 30 civilian observers.

Leamon Hunt, a career U.S. diplomat, is the director general of the force.