The Israeli government will consider a request by the United States to free the Shiite Moslem prisoners held by Israel in order to end the ordeal of the hijacked TWA aircraft and its American passengers and crew members, well-placed Israeli sources said tonight.

"Israel will not enter any negotiations on the exchange of the hostages on the TWA plane for the prisoners held by Israel," the sources said. "If the U.S. government will turn to Israel on a senior level and request the release of the Shiite prisoners for the hostages, the government of Israel will consider it. So far, there has been no request from the U.S. government."

The statement, which was volunteered by the Israeli sources, appeared to be an attempt to clarify Israel's complex position in the hijacking drama and to place the responsibility for accepting or rejecting the hijackers' demands squarely on the Reagan administration.

Earlier today, a variety of sources said that if a formal request to free the Shiite prisoners were made by the United States, Israel would have little choice but to comply.

Although Israeli officials have said they intend to release all of the Shiite prisoners soon, they are clearly reluctant to take that step now under the threats of the hijackers, who are demanding the prisoner release in exchange for the lives of the American hostages. But the officials made clear, as tonight's statement by Israeli sources was apparently intended to reinforce, that they would have to be guided by U.S. wishes because American lives were at stake.

Officials here appeared intent on making clear both to the Reagan administration and the U.S. public that Israel would not stubbornly hold its Shiite prisoners. At the same time, the Israeli government, in part because of the controversy raised here over its earlier agreement to a massive prisoner exchange that included the release of large numbers of convicted terrorists, was clearly demanding a reason to act.

The Israeli sources denied that they were "inviting" a request from the Reagan administration. "Maybe the message coming out of Israel is not clear, and maybe the U.S. government needs this," the sources said. "There is no situation where we can just let them go. It has to come with a request from the U.S. It has to be part of a deal, and the deal has to start with a request from the Americans."

The Israeli position became clearer amid continuing contacts between the government here and U.S. officials and as the Israeli Cabinet met in tight secrecy to discuss the hijackers' demands.

Earlier today, a senior Israeli official strongly denied reports from northern Israel that roads were being closed and buses rounded up, possibly indicating the imminent transfer of the prisoners to southern Lebanon from the Atlit Prison near the Israeli coast south of Haifa.

"It's nonsense," the official said. "There are no buses or anything else. We haven't received any requests from the Americans, so why should we initiate anything? We're just watching the situation. We aren't doing anything."

The U.S.-Israeli contacts on the hijack situation began yesterday and were conducted largely by Defense Minister Yitzhak Rabin and Robert Flaten, the charge d'affaires at the U.S. Embassy in Tel Aviv. Flaten, who until the arrival of Ambassador-designate Thomas Pickering is the highest ranking offical at the embassy, initiated the discussions, Israeli sources said.

Meanwhile, Rabin reported on the hostage situation during today's regular weekly meeting of the Israeli Cabinet. The Cabinet convened as a "ministerial defense committee," a forum in which secrecy is required by law, and this was reinforced by Prime Minister Shimon Peres, who formally requested "no public comment by government ministers or representatives on this subject."

Most of the Lebanese Shiite prisoners whom Israel holds were rounded up during the series of raids on southern Lebanese villages by the Israeli Army earlier this year. They were first confined at Israel's Ansar prison camp in southern Lebanon, and later transferred to the Atlit Prison in Israel when the Ansar facility was dismantled as part of the Israeli withdrawal from Lebanon.

Israeli officials have said that they plan to free all of the Lebanese prisoners, with the pace of their release linked to the security situation in southern Lebanon. Two weeks ago Israel was on the verge of freeing about 340 of the Shiites, but their transfer back to southern Lebanon was called off at the last minute.

One official said today that the delay was due to unexplained "technical problems," but Israeli radio reported that it was because of an increase in the number of attacks in southern Lebanon on Israeli soldiers and the Israeli-backed South Lebanon Army militia.

Israel has no interest in holding the Lebanese Shiites indefinitely, and Israeli officials concede that their earlier transfer to Israel was a technical violation of international laws dealing with the treatment of civilian detainees. But the demand to release them now was a challenge to Israel's policy of never compromising with terrorists and came against the backdrop of considerable controversy here over what many saw as an earlier serious breach of that policy that may have contributed to the hijacking.

Last month, Israel released 1,150 prisoners, most of them Palestinian and many of them convicted terrorists, in exchange for the freedom of three Israeli soldiers who had been held by the Damascus-based Popular Front for the Liberation of Palestine-General Command. The unprecedented action, in which more than 600 of the freed prisoners were allowed to return to their homes in Israel and the Israeli-occupied West Bank and Gaza Strip, caused an uproar here and charges that it would only encourage renewed attacks against Israel.

In view of these circumstances, it was regarded as unlikely that Israel would free the Shiite prisoners voluntarily in an effort to end the hijacking drama. While Israel plans to release all of the prisoners eventually, one official said, "now they have made it more complicated. If we let any of them out now, it would look like we are giving in."