Israeli Foreign Minister Yitzhak Shamir said yesterday that a new multinational force, perhaps including U.S. troops, may be needed in northern and eastern Lebanon to preserve peace and restore Lebanese government control in the area.

At the same time he continued to oppose the presence of such a force along Israel's borders in southern Lebanon.

Shamir said that after Palestine Liberation Organization, Syrian and presumably Israeli troops are withdrawn from Lebanon, the new Lebanese government of President Amin Gemayel might want an international force similar to the one now in Beirut sent to the northern and eastern areas of the country to assist the Lebanese Army in guarding against infiltration. He made his remarks at a breakfast meeting with reporters and editors of The Washington Post.

He said he thought it was "unrealistic" to consider stationing a similar force near Israel's border with southern Lebanon.

"It's not for an international force," the Israeli foreign minister said.

"To send troops to southern Lebanon knowing . . . these troops would be exposed to a constant danger of being attacked, of being killed or wounded, I think it's not realistic. And thus it is in our interest to prevent such developments."

Shamir reiterated the Israeli Cabinet's withdrawal proposal for a southern Lebanon security zone. This has caused a problem for both the United States and the Lebanese government because of the Israeli desire to assign a major role in policing the zone to the Israeli-backed Christian militia forces headed by Saad Haddad, a former Lebanese Army major.

Later, when Shamir was asked if Haddad's militia would have a role in Israel's peace-keeping plan for southern Lebanon, he said, "I'm talking about the Lebanese Army. I hope Haddad will be included in the Lebanese Army. It's not a condition. I hope this will be the solution."

On Thursday, Paul Wolfowitz, head of the State Department's policy planning staff, said in remarks to the Washington Press Club that he could envision a function for international peace-keeping forces in both southern and eastern Lebanon. Administration offficials suggested that U.S. participation in such forces might have to be considered as "the option of last resort."

But, administration spokesmen at the State Department and White House said yesterday that there are "no plans" for sending additional U.S. troops to Lebanon. In private, however, U.S. officials, while acknowledging that is the case, said the administration still must come to grips with the problem of finding a course of action that will satisfy both the Israelis and calm Gemayel's fears about Haddad posing a threat to his government's authority.

There is strong concern in Congress about the Marines already in Lebanon and the deployment of additional troops could bring strong opposition. In addition, Defense Secretary Caspar W. Weinberger and the Joint Chiefs of Staff are unhappy about the presence of Marines in Beirut. Concern about the morale of the troops, who are operating under extremely tense conditions, is such that there has been some discussion about rotating them out of the country every 30 days.

The Lebanese government wants the United States and Britain to send troops to participate in the United Nations Interim Forces in Lebanon (UNIFIL), which now includes 6,000 troops from Fiji, Ghana, Ireland, Nepal, the Netherlands, Nigeria, Norway and Senegal.

That request and a broadened mandate for UNIFIL are expected to be one of the main topics of discussion when Gemayel meets with President Reagan here next week.

Shamir firmly objected to any role for UNIFIL in southern Lebanon in his meeting at The Post. Israel has long considered UNIFIL inadequate because it is lightly armed, small in numbers and because it represents the United Nations, a body Israel sees as being inclined to be sympathetic to the Palestinians.

"The UNIFIL didn't prevent in the past terrorist raids and attacks against us," he said, "and we cannot blame them for it because we don't think that an international force would be able to do this job, to fight with the PLO."

Shamir met with Secretary of State George P. Shultz for about an hour last night after earlier meetings with Vice President Bush and Weinberger. On leaving the State Department, he said only that there had been agreement to continue discussions. "We will be in touch all the time until a common cause is found."