Secretary of State Edmund S. Muskie, taking a cautiously upbeat view of Iraq's proposal for a four-day cease-fire in its war with Iran, said today he hoped it would lead to negotiations and end the fighting.

At a news conference here, Muskie spoke about the Iraqi offer in terms that differed from the assessment being expressed privately by some U.S. and other Western diplomatic sources.

These sources have described the Iraqi proposal, forwarded to the United Nations yesterday, as an apparent attempt to maneuver Iran into accepting as a fait accompli the territorial gains made by Iraq in the 11 days since its forces crossed the Iranian border.Since Iran has vowed to keep fighting until it wins back its territory, the Iraqi proposal is not regarded here as an initiative capable of resolving the conflict.

However, Muskie, in his public comments today, indicated he is inclined to accept Iraq's offer at face value as a legitimate response to the peace mission undertaken by Pakistani President Mohammed Zia ul-Haq on behalf of the Islamic countries within the United Nations.

"I would hope this initiative would lead as soon as possible to a cease-fire and then to negotiations of the sort that would end the dispute," Muskie said. a

The secretary, who today ended two weeks of consultations during the U.N. General Assembly meeting, kept turning aside questions about how the war might affect the 52 American hostages in Iran and the stability of the Persian Gulf region, which provides roughly 60 percent of the world's oil supply.

While conceding that "the risks and consequences of escalation pose very difficult problems," he said, "I prefer to describe the situation as it appears to be at the moment and not speculate on hypothetical possibilities."

He said that "the fighting seems to have diminished in the last couple of days," and he noted so far both Iran and Iraq have shown "deliberate restraint" toward neutral shipping and have not impeded the transporting of oil through the Persian Gulf.

In offering this assessment, Muskie caused a brief flurry of confusion when, responding to the questions about the possibility of the oil flow being choked off, he said that the United States is involved with its allies in "discussions of a technical level and contingency basis."

It was not clear whether he was referring to discussions about sharing arrangements if there is a worldwide oil shortage or military action to keep open the Strait of Hormuz, which commands the entrance to the gulf.

However, State Department spokesman John Trattner said later that Muskie was talking only about discussions on possible sharing or pooling arrangements and had not intended to imply that any talks are going on about joint military action.

U.S. officials also said privately that, in the early days of the fighting, the United States had consulted very informally with some allies about the possible need for naval action to keep the strait open. But, the officials added, that concern has lessened greatly as shipping in the gulf has gone on unimpeded, and they insisted that no discussions about allied military moves are under way or contemplated.

Later in the day, however, the Pentagon announced that the United States has begun "exploratory discussions" with allied nations about the possibility of joint naval action in case of a threat to the Strait of Hormuz.