Reagan administration officials insist publicly that they won't withhold military and economic aid as a means of pressuring Israel to be more agreeable to the latest US Mideast peace initiative.
But there are clear signals that aid to Israel may be an important factor in Middle East diplomacy in the months to come. Legislation that would increase such aid is stalled on Capitol Hill. And there are critical rumblings that could become sharper after the November election.
The General Accounting Office (GAO), Congress's watchdog, has launched a broad and deep investigation of aid to Israel. This is expected to sharpen growing congressional interest in how that country spends the large amount of aid supplied each year by the United States, and how it uses weapons provided by Uncle Sam.
Some in the armed services are complaining about the amount of military aid going to Israel and Israel's apparent hesitancy to share intelligence gained from fighting in Lebanon. The administration itself is making no move to proceed with the sale of another 75 F-16 fighters Israel seeks or lift the suspension of ''cluster'' artillery shells.
With the exception of 1979, when aid to Israel was boosted as a result of the Camp David accords, Israel between 1977 and 1980 received about $1.8 billion in US loans and grants each year. This past year, loans and grants have totaled $2. 2 billion. About $1.4 billion of this has been for military aid, the rest for economic assistance. With this money Israel has obtained just about every ground and air weapon in the US arsenal, including the most sophisticated.
For fiscal year 1983, which begins in three weeks, the Reagan administration wanted to increase military aid to Israel to $1.7 billion. In their respective foreign aid bills, House and Senate committees agreed to this jump of some $300 million.
But because of budget considerations and concern about Israel's military actions in Lebanon, Congress hasn't passed the bill - nor is it likely to in the near future, according to congressional sources.
''The foreign aid bill is floundering,'' says a Senate Foreign Relations Committee source. ''Already the Israelis have to be worrying about (fiscal year) '84 . . . that's being written right now.''
''I do not right now see the environment for aid to Israel improving under a continuing resolution,'' observes another source with the House Foreign Affairs Committee.
Even before the war in Lebanon, President Reagan's peace initiative, and Israel's rejection of that proposal, the GAO had on its own begun to investigate aid to Israel. But progress has been slow: Last spring the US Embassy in Tel Aviv, citing sensitivity on Israel's part, asked that the study be delayed until Israel's withdrawal from Sinai was complete. More recently, the failure to pass a 1982 supplemental budget bill froze travel money for GAO investigators.
The GAO probe now is expected to be completed early next year. One of the more difficult subjects to be studied is whether Israel violated the US law stating that American weapons be used for ''defensive'' purposes only.
''That's a very difficult question, one that certainly bothers a lot of people,'' said Stewart Tomlinson, the GAO expert on foreign military assistance who is heading the investigation.
For the record, Pentagon officials deny that Israel has been withholding military intelligence gained from the recent war in Lebanon or that its vast US-supplied arsenal takes away weapons from American forces.
''There's a normal ongoing exchange of intelligence,'' said Air Force Col. Kenneth McKim, the Pentagon's Israel desk officer. He adds that under the Arms Export Control Act, weapons are ''not for sale to anybody until our units are up to an acceptable level.''
But at a recent gathering of several hundred US military officers at the Naval War College in Newport, R.I., applause broke out when one participant said: ''It appears that about one-third of our military aid is going to Israel. . . . Isn't that a disproportionate amount for a country of 3 million people?''
Another Marine officer about to leave for the Middle East told those in his discussion group, ''We are letting Israel set our foreign policy.''
Some administration sources have been privately saying that Israel hasn't been totally cooperative with the US in providing details about why US-made weapons prevailed so handily over Soviet weapons.
Israel wants the US to lift what it sees as sanctions barring the shipment of ''cluster'' artillery shells and F-16 fighters. The US is investigating reports that cluster bombs (designed for use against lightly armored vehicles) were used by Israel in areas heavily populated by Palestinian civilians.
As a result of the Israeli invasion of Lebanon, Mr. Reagan has yet to formally notify Congress of a proposal to sell an additional 75 F-16s to Israel. Even if he were to do that immediately, it most likely couldn't be approved by Congress this year due to time taken up by the fall elections.