Amid growing Israeli complaints that Egypt is violating the peace treaty between the two countries, two top U.S. State Department officials have been ordered to the Middle East to attempt to resolve disputes before the final Israeli withdrawal from the Sinai Peninsula scheduled for April 25.

Nicholas Veliotes, the assistant secretary of state for Middle East affairs, met with Prime Minister Menachem Begin and other top Israeli officials today, and Deputy Secretary of State Walter Stoessel is expected here Thursday to begin a diplomatic shuttle between Jerusalem and Cairo to resolve remaining snags in the pullback.

The U.S. diplomatic effort began as Begin charged today that while Israel is scrupulously observing the "letter and spirit" of the treaty, Egypt does not always do the same. Deputy Prime Minister Savid Levy, in a speech to the Herut faction of the Likud Party, warned that Israel will not complete its withdrawal from the Sinai if Egypt does not want it to do so.

In Washington, the initial White House announcement of Stoessel's mission gave the impression that the State Department's number two official was being sent to defuse the threat of an Israeli invasion of southern Lebanon. But later, State Department spokesman Alan Romberg said the trip was related to "some things that need to be worked out" in connection with the Sinai withdrawal.

Romberg would not specify what was involved, but department sources said privately that Stoessel's main goal would be to help iron out remaining disputes about the exact demarcation of the border. Romberg stressed that the United States is "fully confident" that Israel and Egypt intend to carry out the territorial turnover on schedule.

Romberg said maintenance of the cease-fire between Israel and Palestinian guerrillas in Lebanon is "crucial . . . at this important time in the Mideast process," and he said Stoessel "obviously would be prepared to address all areas of tension." But he said that "the principal focus" of his mission would be the Sinai withdrawal.

Veliotes also met with Foreign Minister Yitzhak Shamir and Defense Minister Ariel Sharon. Informed Israeli sources said Shamir told Veliotes about Israel's concern over the border demarcation disputes, alleged Egyptian violations of the military clauses of the peace treaty, signs of increased ties between Egypt and the Palestine Liberation Organization, and Egypt's growing rapprochement with Arab countries that severed relations with Cairo after the Camp David accords were signed in 1978.

Shamir, the sources said, complained to Veliotes about Egypt's stance at the nonaligned conference in Kuwait last week, at which the Egyptian delegate outlined a proposal for a Palestinian state in the West Bank and Gaza and simultaneous recognition by the PLO and Israel of each other, without mentioning the autonomy proposals called for in the Camp David accords.

An Israeli government source familiar with the Shamir-Veliotes discussion said the Egyptian position at Kuwait "contradicts" the Camp David accords.

"We don't oppose ties between Egypt and the Arab world, as long as it is not done at Israel's expense. Maybe what happened at Kuwait is an example of trying to improve ties to Arabs at our expense," the source said.

The Israeli concern over the treaty appeared to reflect both an increasingly jittery outlook on the impending withdrawal and a practical desire to apply pressure on Egypt and extract as many concessions as possible before April 25.

Israel and Egypt are still in dispute over the demarcation of 16 border points. Sharon is due to visit Cairo later this week in an effort to resolve the border disputes. If no agreement is reached, it is expected that they will be put to arbitration.

Israeli officials would not provide details of the alleged increase of Egyptian ties to the PLO, although there have been complaints about a PLO office in the Egyptian Sinai town of El Arish and statements by Egyptian officials calling for U.S. and Israeli recognition of the PLO.

The Israeli officials would not say what complaints Israel has about the military annex to the treaty. They are believed to involve technical violations in Sinai zones where demilitarization or limits on forces apply. Israel also has voiced concern about the smuggling of weapons and explosives through the Sinai to PLO guerrillas in the Gaza Strip.