President Reagan's Middle East peace initiative has seriously complicated efforts to revive the Palestinian autonomy talks, and they must be put off for months, senior Israeli officials said today.

Only two weeks after Prime Minister Menachem Begin told visiting U.S. congressmen that Israel would not wait for the withdrawal of Israeli and Syrian troops from Lebanon before seeking a resumption of the autonomy talks, Foreign Minister Yitzhak Shamir said today that the situation in Lebanon should be settled before the autonomy negotiations are resumed.

At that point, Shamir was quoted as telling ambassadors from the 10 European Community countries, "The time will be right to resume the autonomy talks."

Officials said this could take months, and they placed the blame for any delays on the Reagan proposals, which the Israeli Cabinet last week bluntly rejected.

"Obviously some time will have to elapse because this is not the right atmosphere," a senior official said. "It may be that we are months away. I truly think we will continue with the peace process. But now, because of this American position that has complicated matters, we are not so close anymore."

The Camp David talks on the proposed interim five-year period of autonomy for the Palestinian inhabitants of the West Bank and Gaza Strip were unlikely to resume soon in any event because of Egyptian insistence that Israel first withdraw its forces from Lebanon. But before Reagan's proposals were made in a letter to Begin last week, Israeli officials had expressed eagerness to resume the autonomy negotiations and had seemed unconcerned about Egypt's announced intention to boycott the talks.

Today's comments by Shamir and other senior officials were a clear indication that Israel will be more than satisfied with a continued deadlock in the negotiations while it pursues its policy of establishing Jewish settlements in the occupied territories.

In his letter to Begin and in a speech last week, Reagan called for an immediate freeze on settlements to help revive the autonomy talks and suggested that the future of the West Bank and Gaza should involve an unspecified link to Jordan.

The Israeli government quickly rejected the proposal and, in a direct challenge to Reagan, yesterday approved three new settlements in the West Bank and gave official government status to an existing Jewish community in Gaza.

It has become increasingly clear that the president is paying a heavy price now for his earlier acquiescence in the Begin government's settlements policy.

Unlike former president Carter, Reagan said early in his term that he did not consider the settlements to be illegal, and until last week he had made no major public objections to their continued establishment by Israel.

Israeli officials today were quick to note the earlier silence from Washington, saying they saw no connection between the settlements policy and the autonomy talks.

In a radio interview, Construction and Housing Minister Yitzhak Modai said, "now you will, of course, notice that on all previous occasions, or most previous occasions, where new settlements have been set up, the American administration did not react this way and that by itself is a confirmation that that was in line with the American understanding of Camp David."

While the Begin government remained adamant in its opposition to the American initiative, an internal debate over the Reagan proposals is beginning to take shape here and may come into better focus Wednesday during a special session of the Israeli parliament called to discuss it.

The main opposition Labor Party has endorsed the U.S. proposals as worthy of negotiation, and today Amnon Rubenstein, the head of a small opposition party on the left, called yesterday's decision to authorize new settlements "an unnecessary provocation."

By linking the future of the autonomy talks to Israeli and Syrian withdrawal from Lebanon in his talk with European ambassadors, Shamir in effect suggested an open-ended delay in the negotiations. Israeli officials have publicly expressed confidence that a mutual withdrawal agreement can be reached with Syria, but in the meantime the Israeli Army is making preparations to remain in Lebanon through the winter.

According to Israeli officials, Shamir told the ambassadors that Israel intends to have discussions with Lebanese authorities about "security arrangements" along Israel's northern border with Lebanon.

Officials said Shamir did not mean to imply Israeli interest in a continued military presence in southern Lebanon, although they did not rule out that the possibility might emerge from talks with Lebanese authorities.

Defense Minister Ariel Sharon suggested that if Lebanon does not sign a peace treaty Israel will retain control over southern Lebanon, The Associated Press reported. Speaking at the border town of Qiryat Shemona, Sharon said that if a treaty is not signed, southern Lebanon will have "a different status."