President Carter submitted his controversial Middle East arms sales package to Congress yesterday but dropped his public threat to withdraw the entire package if Congress blocks any part of the proposed sale of warplanes to Israel, Egypt and Saudi Arabia.

In what amounted at the least to a rhetorical retreat, administration officials said the president will now "reserve judgment" on his final action until after Congress acts on each of the sales separately.

But there were suggestions from the officials that Carter still intends to carry out his threat if necessary and had agreed to drop references to it as an all-or-nothing "package" in order to soothe "congressional sensibilities."

"You're never going to hear the word package used again," one official said.

The $4.8 billion sale involves supplying 75 F16 and 15 F15 fighters to Israel, 50 F5 fighters to Egypt and 60 F15s to Saudi Arabia.

The key issue in the package is the Saudi plane sale, which is adamantly opposed by Israel and its supporters in Congress. Carter's determination to supply the Saudis with the planes - the most sophisticated fighter in the U.S. arsenal - is expected to set off a bitterly emotional debate in Congress and represent a severe test of strength between the administration and the so-called "Israeli lobby."

Under the law, any of the four separate sales could be blocked if both the House and Senate pass resolutions of disapproval within the next 30 days. Otherwise, the sales would go through.

As the proposed sales were sent to Congress, administration officials continued to express confidence that they have enough votes to beat back attempts to block the Saudi sale. In that event, Carter will not be faced with the choice of carrying out his earlier threat or seeing his rhetorical retreat of yesterday turned into complete surrender.

Under the law, Congress must act on each of the sales separately. But the president has insisted repeatedly that, in his mind, they are a single package, with each sale dependent on approval of the others.

Given the extent of this presidential commitment, and given the United States' reliance on Saudi Arabia for oil and as a moderate force in the Arab world. Carter would appear to have little choice but to carry out his earlier threat should Congress block the Saudi plane deal.

Yesterday's announcement, with its dropping of the references to a package, came after days of intensive negotiations between administration officials and some key supporters of Israel's position on Capitol HIll.

"In submitting these proposed sales to Congress on the same day, the administration is not attempting to place conditions on the scope of congressional review or the action by Congress," Secretary of State Cyrus R. Vance said in making the announcement at the White House. "Indeed we understand that the Congress will want to review these important transactions separately and with great care.

"At the same time," Vance continued, "the responsibility of the presidentf for the conduct of foreign affairs requires that he reserve judgment on the ultimate action to be taken until he has had an opportunity to review the action taken by the Congress on the proposals announced today."

But while the word package was dropped, the suggestions that Carter has not altered his position were not. Repeatedly referring to the proposed arms sales as "balanced," another administration official told reporters:

"Inherently, you can't consider one of these countries separately or isolated from the other countries."

The official said the language of the announcement did not mean that the President's earlier statements about the all-or-nothing nature of the sales no longer applied. "We are simply not using that terminology," he said.

Vance, in a letter to Sen. Frank Church (D-Idaho) yesterday, encouraged congressional review of components of the sale "on their individual merits," a declaration which Church immediately interpreted as a significant shift in Carter's position.

"It appears from the secretary's letter that the president has untied the package," Church said. "I think this clears the way for hearings before the Senate Foreign Relations Committee in the near future on the merits of each individual sale."

An aide to Church, while conceding that the sales never were linked in a "technical sense," ascribed the change in Carter's posture to an abandonment of his "all-or-nothing" statements, while leaving the door open to negotiations.

The Foreign Relations Committee discussed the arms sale in closed session yesterday before the proposals were delivered. Another meeting is scheduled for 2:30 p.m. Monday to attempt to work out a schedule of hearing, committee aides said.

Sen. Jacob K. Javis (R-N.Y.), also a member of the committee and an pponent of the sale of the warplanes to Saudi Arabia, said he did not interpret Vance's statement as a major shift in position.