Israel's ambassador to the United States, Moshe Arens, was sharply criticized here today for reportedly urging a six-month freeze on Jewish settlements in the occupied West Bank as an Israeli response to President Reagan's Middle East peace initiative.

In a sign that Israel plans no change in its policy, Dan Meridor, the Cabinet secretary, said following today's regular Cabinet meeting that settlement activity would continue in the occupied territories.

The state-run Voice of Israel radio reported Arens' proposal this morning and said it had been rejected out of hand by Prime Minister Menachem Begin. According to the report, Arens argued that a temporary freeze on settlements would assuage American anger with Israel and might help to entice Jordan's King Hussein to join the Camp David peace framework.

In another development today, the Israeli military command announced that two surface-to-air missiles were fired from inside Syria at Israeli planes flying a reconnaissance mission over the Bekaa Valley in eastern Lebanon. Details on Page A18.

Israeli Foreign Minister Yitzhak Shamir said on state television: "We regard the attack today as a very serious violation of our cease-fire with Syria and expect Damascus to take immediate measures to halt any further similar actions.

"Aggressive actions such as this one could delay evacuation of foreign forces from Lebanon."

On the settlements freeze, Geula Cohen, a nationalist member of the government coalition, said that if Arens had made the suggestion he should be recalled from Washington and dismissed from the diplomatic post.

In another reaction, the Council of Jewish Cities and Settlements in Judea and Samaria (the biblical names for the West Bank) cabled Arens for a clarification of his proposal, telling him that calling for a temporary freeze on the settlements is "the same as asking a Jew to convert for six months."

A spokeswoman for the council said that Arens' "prolonged absence in the United States might have put him a bit out of touch with the reality of the situation in Judea and Samaria today."

Arens apparently proposed the six-month settlements freeze to Begin in September, shortly after the president unveiled his peace initiative. The Reagan plan calls for the occupied territories to be linked in the future to Jordan.

Asked about Arens' reported proposal, Israeli Embassy spokesman Nachman Shai said, "The ambassador does not want to comment in any way" on leaks about messages between the embassy and the government. "He cannot say what was or wasn't in his cables to the government," Shai said, "nor can he say what was or wasn't in cables from the government to him." The spokesman said that Arens' "opinion on settlements is well-known and he hasn't" changed his views recently.

Shai said that in answer to a question from an Israeli journalist Sunday afternoon, Arens made clear that he opposes a freeze on settlements in the occupied territories.

In a speech outlining his proposals, President Reagan called for an immediate freeze on new Israeli settlements in the occupied territories, a step that he said "more than any other action could create the confidence needed for wider participation" in the Middle East peace talks.

Arens, who opposed the return of the Sinai to Egypt and the Camp David peace accords, is one of the more hard-line members of the Begin government. He was elected to the Israeli parliament with Begin and is not a career diplomat. Thus it would be surprising if he advocated a settlements freeze, even of only six months.

Begin rejected the Reagan plan from the start and, in an indication of his likely attitude toward the freeze proposal, approved along with other government members a number of new Jewish settlements in the West Bank and Gaza Strip less than a week after Reagan made his initiative. The Cabinet meeting was dominated by the question of Israel's deteriorating relations with Egypt and an Egyptian call for the resumption of negotiations over a disputed strip of land on the Sinai border.

The land, known as the Taba area, is just south of the Israeli city of Elat and is the center of the only border dispute left unresolved by Israel's return of the Sinai to Egypt in April. Although only a few hundred yards of land are involved, it is valuable beach-front property on which an Israeli company is building a luxury hotel.

According to reports from Cairo, Egypt formally has asked Israel to postpone the opening of the hotel, planned for mid-November, until the border dispute is settled.

Such a postponement, however, appears unlikely, particularly in light of mounting Israeli dissatisfaction with the overall state of relations with Egypt and the continued absence from Israel of Egyptian Ambassador Saad Mortada. Mortada was recalled to Cairo for "consultations" in September following the massacre of Palestinian refugees in Israeli-occupied West Beirut.

Meridor said after the Cabinet met that Israel is willing to resume the Taba negotiations, but only if other aspects of Egyptian-Israeli relations improve at the same time.

"There are negotiations and contacts on many other issues, and we don't think it proper that all the others, or many of the others, are frozen, and just this issue is resumed," Meridor said.

Meridor refused to say whether the Begin government will demand the return of Mortada as the price of a resumption of the Taba negotiations, although that is the widespread impression here.