Israeli concern about U.S. policy in the Middle East has led Prime Minister Menachem Begin's government to warn the Reagan administration that it is seriously considering such drastic actions as military strikes against Lebanon and possibly Jordan.

With less than two months remaining before Israel's scheduled return of the Sinai Peninsula to Egypt, the Jewish state has become increasingly open in its declarations of unease. Last week, the new Israeli ambassador here, Moshe Arens, bluntly cautioned that the United States can expect a new invasion of southern Lebanon unless the artillery and rockets in the hands of Palestine Liberation Organization forces there are removed.

In addition, the acknowledgment Sunday by Jordan's King Hussein that he soon will ask to buy advanced U.S. weaponry has threatened a collision course that could leap beyond the bounds of diplomatic disagreement into an Israeli attempt to settle the dispute by force, informed sources here say.

Even before Hussein publicly signaled his intentions, Israeli Defense Minister Ariel Sharon warned that his country will not permit Jordan to acquire American mobile antiaircraft missiles and sophisticated jet fighters.

Elaborating on Sharon's remarks to a group of reporters last week, Arens said the defense minister was reflecting the growing view in Israeli military circles that the only way for Israel to retain its "qualitative edge" against the Arab countries would be a "preemptive strike" against any country that threatens to tip the Mideast military balance.

These ominious rumbles are a sign that U.S.-Israeli relations, which during President Reagan's first year in office resembled a roller-coaster ride, are roaring toward another sharp dip.

The reasons include the Begin government's inherently confrontational style. They also include what U.S. officials concede is the high anxiety quotient becoming evident in Israel at a time when it is about to lose the "Sinai security blanket" that has served as a buffer between it and Egypt since 1967 and when Egyptian President Hosni Mubarak appears more intent on healing his breach with the Arab world than on reinforcing Egypt's peace treaty with Israel.

In another expression of the jitters afflicting the Middle East, Egyptian Ambassador Ashraf Ghorbal broke off a vacation at home to return here yesterday with a message from Mubarak that the ambassador asked Secretary of State Alexander M. Haig Jr. to deliver to Reagan.

Diplomatic sources said the message contained an explanation of the Egyptian side of the argument that has threatened to derail Mubarak's scheduled trip to Israel because of his reluctance to antagonize Arab opinion by visiting Jerusalem as the Israelis demand.

Increasingly, however, Reagan's critics have argued that much of the blame is rooted in the inherent contradictions of the administration's two-track Mideast policy.

That involves the idea that the United States simultaneously can pursue a settlement of the Arab-Israeli dispute, while seeking to put together what Haig calls "a strategic consensus." That refers to the goal of cultivating stronger military ties on a country-by-country basis with both Israel and western-oriented Arab states that share U.S. concerns about threats to the region from the Soviet Union and its alleged surrogates.

The administration has argued that America's vital stake in the Middle East's oil and strategic location makes this military emphasis an imperative. It contends further that its two-track approach can be pursued without peril to Israel's security, that establishing closer military ties in the Arab world can be done in ways that do not impinge on the peace process and that indeed, in Haig's frequently used phrase, the two aims are "mutually reinforcing."

The critics charge, though, that in actual practice the policy has seen the United States ignore the peace process while putting its main emphasis on flooding receptive Arab countries with American arms--a process that permits Israeli hardliners to argue that the United States is tilting toward the Arab side and sacrificing Israel's military edge to the effort to buy Arab friendship.

To substantiate their indictment, the critics note that the major U.S. policy moves of the past year have involved such things as the controversial sale, over vehement Israeli objections, of an $8.5 billion package of sophisticated aircraft to Saudi Arabia and a scramble to enlist such Arab countries as Egypt, Saudi Arabia, Jordan, Morocco and Oman in a series of cooperative military arrangements.

By contrast, the critics note, the administration, during the same time, shied away from priority attention to the effort, under the Camp David peace process, of trying to achieve an Egyptian-Israeli agreement on Palestinian autonomy. Then, when Haig finally did address the issue, he put U.S. participation in the hands of an unknown aide.

In response, administration officials contend that their two-track approach is both valid and viable.

As one senior U.S. official put it, "There are severe difficulties because we're dealing with two camps at odds with each other. They are suspicious, and they don't trust us. The problem is to make the policy believable and acceptable to both sides by keeping our promises to each and establishing our credibility."

However, as the current controversy over arms sales to Jordan indicates, the "explaining" has fallen far short of what is needed to overcome suspicions about what kind of game Washington is playing. At issue in this case is U.S. concern over Hussein's announced decision to buy mobile antiaircraft missiles from the Soviet Union.

On a trip to the Middle East last month, Defense Secretary Caspar W. Weinberger, making a new effort to steer Hussein away from the Soviet deal, raised with him the possibility of the United States selling U.S.-improved mobile Hawk missiles and possibly F16 jets. Although precisely what was said or promised remains unclear, Weinberger is understood to have discussed the administration's willingness to explore the chances of getting such a sale past the opposition of Israel's supporters in Congress.

Such a move would reverse past U.S. policy of providing Jordan only with stationary missiles that could not be moved into positions against Israel. As a result, reports of Weinberger's discussions touched off an immediate uproar in Israel, which is still smarting over Reagan's sale of advanced radar surveillance planes to Saudi Arabia, and in Congress, where Israel's backers would regard the move as an abrogation of existing understandings with the executive.

Complicating the matter considerably were some press reports, including one given prominent display in The New York Times, quoting Pentagon officials in Weinberger's entourage as saying the United States was redirecting its policy away from Israel. Subsequently, the administration responded, apparently correctly, that these reports were based on a misunderstanding and that the talk of "redirecting policy" referred not to the Arab-Israeli conflict but to a shift in the emphasis of U.S. military cooperation with Arab countries from external threats to internal subversion.

However, the response, involving tortuous, hard-to-follow explanations about what anonymous officials did or didn't say, never really overcame the chilling effect that the original reports had on Israel and its supporters. Nor was the matter put to rest by a Reagan letter to Begin reiterating U.S. policy of maintaining Israel's "qualitative technological edge" in weaponry and stating that no requests had been received nor decisions made about new sales to Jordan.

In fact, the administration's reassurance now seems somewhat disingenuous in the light of Hussein's public declaration that, while he intends to go ahead with the Soviet deal, he also will ask for American missiles and aircraft. That means the administration, which reacted with its now stock answer that it hasn't yet received a Jordanian request and has made no decisions, will be unable to rely on that response much longer.

Instead, the administration almost certainly soon will find itself in a tight spot. If it says no to Jordan, it runs the risk of alienating Hussein and possibly driving him deeper into an arms-supply relationship with the Soviets. But if it agrees to the Jordanian request, it faces another bruising battle with Congress and an increasingly desperate Israeli reaction that could well tip the debate there about preemptive strikes in favor of hawks like Sharon.

In private, administration sources say there is little doubt that the Pentagon, whose main interest is in getting the maximum amount of American military influence and weaponry into the region, favors going ahead with the sale to Jordan. That has caused considerable speculation about yet another policy clash between Weinberger and Haig, who is known to show more concern about Israeli anxieties.

In actuality, however, both senior U.S. officials and Israeli representatives like Arens agree that the differences are largely tactical. They say that, while it is true Haig advocates a more gradual and cautious approach to the timing of an accommodation of Jordan's requests, he is as wedded to the "strategic consensus" concept as anyone in the administration.

These sources say Haig believes it is possible to give Hussein the arms he wants while keeping Israel pacified through a continued combination of reassurances, aid and, when the time is ripe, such steps as successful easing of the tensions along the Lebanese border and a reactivation of the peace process.