Egypt cautiously welcomed President Reagan's Middle East peace intiative today, and visiting Secretary of Defense Caspar W. Weinberger said he was very encouraged by the Egyptian reaction.

A spokesman said that the Cabinet welcomed the positive aspects of the Reagan plan, which can provide a basis for forging ahead with the peace process. Nevertheless, he added, the Cabinet has some reservations and would continue to study the initiative.

The brief statement was released following a special Cabinet meeting convened to draft an official reaction to the new U.S approach to a negotiated settlement in the region. President Hosni Mubarak had earlier discussed the plan with Weinberger, and held a separate meeting with his top aides to study it.

Weinberger, who is visiting Egypt on the last leg of a tour in the area, described his meeting with Mubarak in the port of Alexandria as very explicit and constructive. He added that he was encouraged by the 75-minute conversation, but refused to divulge any details.

The plan outlined by Reagan in a speech Wednesday was viewed here as a gesture toward moderate Arab states that share an interest in restoring U.S credibility in the region. Egyptian-American relations had soured following Israel's invasion of Lebanon with Egypt objecting to U.S diplomatic efforts to solve the Beirut crisis separately from the overall Palestinian problem.

Egyptian officials said the new U.S. initiative falls short of a common denominator they have adopted as a goal for a Middle East peace settlement, namely creation of a Palestinian state. The Egyptians interpret the Camp David peace framework as allowing for self-determination and therefore statehood for the Palestinians of the Israeli-occupied West Bank and Gaza Strip at the end of a five-year transition period.

Egyptian officials are pleased that the U.S. plan does not define the Palestinian problem as a refugee problem and insists that Jewish settlement in territories occupied by Israel during the 1967 war be frozen.

Egyptian officials are aware their endorsement of Reagan's idea of linking the West Bank and Gaza to Jordan within the framework of a solution would represent a significant reversal of a stand they have maintained during the last three years in talks with Israel and the United States on Palestinian autonomy. Egypt's reluctance to sign a document determining the status of the Palestinians in those territories has developed into a rejection of that role recently.

The Cabinet statement's stress on a thorough study of Reagan's proposals in the light of Arab and international reactions to it indicated that a detailed Egyptian response might be delayed until after the Arab summit due to convene in Morocco Monday. Most moderate Arab states have reacted favorably to the proposals but their reactions remained vague and unofficial.

The Associated Press reported the following developments:

Exiled Palestinian leaders gathered in the Tunisian capital of Tunis to discuss Reagan's proposals. One Palestine Liberation Organization source in Damascus said a dozen of chairman Yasser Arafat's top aides had firmly rejected the intiative during a four-hour meeting with Syrian President Hafez Assad. Others noted there had been no formal response and said the plan was being studied.

A PLO source in Tunis said a meeting of the 15-member Executive Committee, the first since the Israelis scattered the PLO guerrillas into eight Arab countries, would be held soon at Arafat's new headquarters in Tunis.

The PLO source in Damascus, who said he attended the meeting with Assad, reported that the Syrian president said he would lead the Syrian delegation to the Arab League summit. He quoted Assad as saying he will insist the Arab world take a united stand against the U.S. proposals and forge a "confrontation strategy."

Syria has been officially silent on the U.S. proposals, but the government-run newspaper Tishrin said the plan "leaves nothing for the Arabs but death and slavery."