There is an extensive diplomatic shuffle in the works at the State Department affecting a number of highly sensitive posts, sources say, with a new ambassador going to Kuwait and others selected for Egypt, Lebanon and the Philippines.

Sources say Frank G. Wisner, a career diplomat who is the ambassador in Cairo, will be heading for the Philippines next summer to replace Ambassador Nicholas Platt. Platt has received no new assignment, but a source said he will "get a good job."

Wisner was senior deputy assistant secretary of state for African affairs in 1982-86 and ambassador to Zambia in 1979-82. He was detailed to the Agency for International Development in Vietnam in 1964-68 and later served in Tunis and Dacca, Bangladesh.

Robert H. Pelletrau Jr., now ambassador to Tunisia and the only U.S. official who had been authorized to deal with the Palestine Liberation Organization before the U.S. breakoff of the peace talks, will be heading for Cairo to replace Wisner. No decision has been made on who will replace Pelletrau in Tunis when he leaves next summer.

Pelletrau, a career officer, has been in Tunis for three years. Before that, he served as deputy assistant secretary of defense for near eastern and south Asian affairs in 1980-81 and 1985-87. He also served as ambassador to Bahrain and was deputy assistant secretary of state for near eastern and south Asian affairs in 1983-85.

Ryan C. Crocker, now political counselor to Wisner, is moving up in rank to the tricky post of ambassador to Lebanon later this year, replacing John T. McCarthy, who is scheduled to serve a year as diplomat-in-residence at Howard University and the University of the District of Columbia.

The Beirut post is unusual because the embassy was closed last September for safety reasons after Christian strongman Gen. Michel Aoun attempted to force the United States to recognize his rebel military government.

Crocker, a career diplomat and Arab expert, served as political officer in Beirut during the Israeli invasion.

In addition, President Bush has nominated Edward W. Gnehm to be the next U.S. ambassador to Kuwait. Gnehm, 46, served as deputy assistant secretary of state for near eastern affairs until his June 19 appointment, directing and coordinating U.S. foreign policy for the Arabian Peninsula and Iraq, Iran, Jordan, Syria and Lebanon.

A native of Georgia, Gnehm, a career Foreign Service Officer, was also the deputy chief of mission at the U.S. Embassy in Amman, Jordan, and in Sanaa, Yemen. In 1976, he opened the U.S. Liaison Office in Riyadh, Saudi Arabia, and was among the first U.S. diplomats to reopen the diplomatic mission in Damascus, Syria, in 1974. Other postings included Lebanon, Tunisia, Vietnam and Nepal.