Egypt rejected an Israeli call for resumption of Palestinian autonomy negotiations tonight and said direct talks can continue only when Israel provides clear, written assurances that the status of Jerusalem is part of the discussions.

"For you to negotiate while the other party is taking unilateral steps on the ground, taking advantage of the fact that there is occupation of the West Bank and Gaza, is ridiculous," said Osama Baz, the Egyptian Foreign Ministry's undersecretary.

Baz made his comments at a news conference shortly after Prime Minister Menachem Begin's office in Jerusalem released the text of Israeli's reply to a letter sent late last month by Egyptian President Anwar Sadat demanding assurances on Jerusalem as a condition for continuing the talks.

Baz declined to predict how long the talks might remain suspended. But his remarks provided a strong indication that Eygpt expects a relatively lengthy hiatus, during which Sadat and Begin will exchange messages, and their negotiating teams will remain idle.

"We wrote, they replied, we wrote back, and so on in the exchanges," he said.

The delay, although not sought by Sadat, in some ways meets an Egyptian problem. For some time, Eygptian officials have been reconciled to little or no progress until the American election campaign is over. The problem, they have been telling reporters, is how to keep up the appearance of movement for the next four months. Now that the talks have in effect shifted to a series of message exchanges, time can be played out without real negotiations, but also without an obvious stall.

In addition, Eygptian officials appear determined to demand more explicit assurances this time than the vague U.S. assessment that turned out to be wrong about the law's chances of passage in the Israeli Knesset, or parliament. Baz emphasized that Egypt is dealing directly with Israeli this time in its demands.

'We must see written words and actions," he said.

Egyptian Foreign Ministry officials have made it clear that Sadat wants to help Carter's campaign as much as he can, and it is appreciated here that the Israeli-Egyptian peace treaty is the President's main success story. But at the same time, Baz said, the issue of Jerusalem can no longer be skirted just to keep the talks going.

"The question of Jerusalem imposes itself on the negotiations for establishment of a self-governing authority because many points tough upon that problem," he said. "This is not an issue that can be deferred altogether until the final step of the negotiations."

Baz was at pains to stress that Egypt expects the talks with Israel to continue, however, and he rejected Begin's contention that Egypt has violated its commitments in the peace treaty and Camp David accords.

"We believe that in the end reason will prevail," he said. "We still believe that it is possible to continue the negotiations at the appropriate time and under the proper circumstances."

But he also seemed eager to provide a counter to Begin's call for resumed negotiations, emphasizing that the Jerusalem law in Egypt's view forecloses one of the subjects that was supposed to be negotiated under the Camp David agreements. Israel's continued construction of new settlements and Begin's plans to move his office to East Jerusalem also fall into this category, he added.

"For the last few weeks, Israel has been taking certain unilateral steps with regard to Jerusalem," he said. "We consider this a violation of the agreement by both parties to keep the issue negotiable . . . We are against any movement of the office of the prime minister to East Jerusalem. This is the Arab part of the city and it should not house the office of the Israeli prime minister, because it is part of the West Bank and Gaza, whose status should be determined in the final outcome of negotiations."