Increasingly concerned about the hostility the Arab world is showering on Egypt's Anwar Sadat, President Carter is sending high-ranking delegations next week to visit Morocco and the Sudan, two Arab countries that have been sympathetic to Sadat's peace efforts with Israel.

Sen. Jacob Javits (R.N.Y.) will go to the Sudan next week as a special envoy for Carter, accompanied by Assistant Secretary of State for African Affairs Richard Moose, the State Department announced yesterday. They will meet President Jaafar Nimeri of the Sudan, one of only three Arab heads of states who have openly supported Sadat's peace treaty with Israel.

Nimeri's support for Sadat has won the Sudan's increased aid requests a sympathetic hearing from Javits and other members of the Senate Foreign Relations Committee, which added $10 million to the $50 million in new credits and economic aid sought by the administration this year.

A delegations of U.S. officials headed by Deputy Secretary of Defense Charles W. Duncan will visit Morocco tomorrow and Tuesday for talks with King Hassan II about the Middle East and Morocco's continuing war against guerrilla forces in the Sahara territory.

The trip was announced Friday night by the Pentagon. The announcement noted that Carter had asked Duncan to lead the delegation, but did not explain why the Defense Department would be the lead agency on what is likely to be a Middle East policy review session with the Moroccan monarch.

Secretary of State Cyrus R. Vance and his principal Middle East deputies are currently visiting Egypt and Israel for the ceremonial start of the implementation of the U.S. sponsored peace treaty between those two nations.

Planning for Duncan's visit began about a week ago and was evidently triggered by a suggestion from the Moroccans that talks would be welcome now. Hassan, once a strong supporter of Sadat's peace effort, has been caught in the middle of the polarization created by Sadat's peace bid. Hassan recently hosted the Islamic foreign ministers conference that refused to seat an Egyptian delegation. He has muted his support for Sadat as other Arab states have stepped up their attacks on the treaty.

The Islamic conference named Hassan head of a special committee on Jerusalem, and Moroccan officials have suggested that the committee eventually may provide a forum for Arab efforts to arrange a peace agreement broader than the Egypt-Israeli pact.

Hassan is also likely in his meetings with Duncan to renew his repeated requests for new U.S. arms shipments. those shipments have been sharply reduced because the United States does not recognize Morocco's annexation of the former Spanish Sahara colony and the Moroccans do not feel they can limit their sovereignty by promising not to use arms in the Sahara war with Polisario guerrillas.

The Carter administrtion loosened its restrictions on weapons slightly in March by agreeing to ship $5 million worth of spare parts and ammunition for Morocco's F5 squadron after Polisario raided deep into Morocco. Sales of Sparrow naval missiles and other non-Sahara items also have been approved recently.