The Israeli government today rejected the Middle East peace proposals adopted by the Arab summit conference in Fez, Morocco, calling them worse than similar proposals made last year by Saudi Arabian King Fahd.

The rejection, which had been expected, was announced by Avi Pazner, the senior spokesman of the Israeli Foreign Ministry, who said Israel had not seen the complete text of the Fez declaration.

"But we have enough information to say that Israel cannot consider seriously this plan, which does not contain any substantive new elements that differ from the traditional Arab position," he said.

"The Fez plan is worse at first glance than the Fahd plan, which was rejected in the past by Israel. On top of all the other negative elements, this plan calls for the establishment of a Palestinian state. This idea obviously presents a danger to Israel's existence and underlines the intention of this plan to bring about Israel's destruction in stages."

In a speech in Tel Aviv, Foreign Minister Yitzhak Shamir dismissed the Fez plan as a "renewed declaration of war on Israel," The Associated Press reported.

Characterizing the positions adopted by the Arab leaders as "useless," Pazner said Israel "totally rejects these ideas." He said the Arab states would be better served if they "would immediately open negotiations with us in order to bring peace and prosperity to the region through the signing of peace treaties between each one of them and Israel."

The announcement marked the second time in two weeks that Israel has rejected out of hand suggestions for Middle East peace negotiations. The Israeli government took the same stance toward President Reagan's peace initiative and insists that it will negotiate only on the basis of the proposals in the Camp David accords for an interim five-year period of autonomy for the Palestinian inhabitants of the occupied West Bank and Gaza Strip.

Meeting in the Moroccan capital of Fez, Arab leaders for the first time agreed yesterday on a joint Middle East peace plan offering implicitly to recognize Israel and setting out terms for living in peace with it.

The summit demanded the creation of a Palestinian state with its capital in East Jerusalem, recognition of the Palestine Liberation Organization as the legitimate representatives of the Palestinian people and Israeli withdrawal from the territories it captured in the 1967 Arab-Israeli war.

The proposals were similar to a peace plan advanced last year by King Fahd, then the Saudi crown prince. At the time, however, the strong objections to the Fahd proposals by radical Arab states could not be overcome and an effort to reach agreement at an earlier summit in Fez had to be abandoned.

One of the key reasons for the breakdown of the earlier summit was the next-to-last point in the eight-point Fahd plan that called for recognition of "the right of states of the region to live in peace." This was interpreted in some quarters as an Arab offer of recognition of Israel, which is bitterly opposed by the hard-line Rejectionist Front, although that was never the Israeli interpretation of the phrase.

To overcome the objections of the radical states, the new Arab peace proposals deleted this section and called instead for U.N. Security Council guarantees of peace for countries in the region.

While the Fahd plan was always unacceptable to Israel, officials here said, this decision by the Fez summit made the new plan even worse.

"The Saudis always boasted that Paragraph 7 of the Fahd plan called for recognition of Israel," an official said. "We did not see it that way, but you did have Paragraph 7. The Fez plan deleted this. So if you could say that there were elements in the Fahd plan that were not completely negative, this has now been eliminated in the Fez plan."

The Israeli officials said they considered the plan's adoption a victory for the hard-line Arab states, especially Syria, and they voiced contempt for the United Nations.

"This strengthened the hard-liners," an official said. "What are guarantees, especially from the U.N.? Guarantees are offered instead of peace, instead of recognition. There is nothing new here."

Israeli officials have expressed their desire to resume the Camp David autonomy talks as soon as possible, but in the wake of the Reagan initiative they said the resumption of talks may take months because the U.S. proposals have created a poor atmosphere for negotiations.