The Israeli government reacted mildly today to President Reagan's statement that the United States is willing to meet with a delegation of Jordanians and Palestinians so long as it does not include members of the Palestine Liberation Organization.

Reagan's statement, made last night at a news conference, appeared to open a gap in the heretofore united stand of the United States and Israel opposing such a meeting. Both countries have insisted that only "direct negotiations" between Israel and the Arabs will lead to a Middle East peace agreement, and Israel has said a U.S. meeting with a joint Jordanian-Palestinian delegation would serve as a backdoor maneuver to start an American dialogue with the PLO.

Nevertheless, in a situation that involves delicate considerations of international diplomacy as well as domestic politics here, the Reagan statement was greeted with silence by Prime Minister Shimon Peres and only indirect criticism by Foreign Minister Yitzhak Shamir.

Asked if Peres had any reaction to Reagan's news conference remarks, Uri Savir, the prime minister's spokesman, said, "No."

Shamir's spokesman, Avi Pazner, said the foreign minister wanted to study the Reagan statement, and "the implications are not clear to us."

But in an implied criticism of proposals for U.S. discussions with a Jordanian-Palestinian delegation, Pazner added, "If one wants to further the course of peace, the way to do it is to encourage the Arabs to talk to Israel."

Reagan's comment yesterday came against a backdrop of stepped-up Middle East diplomacy set in motion last month by Egyptian President Hosni Mubarak.

Mubarak offered two versions of a proposal to revive the Middle East peace process. In the first, he called for direct negotiations between Israel and a joint Jordanian-Palestinian delegation, with the United States or Egypt serving as the host. In a revised version of the proposal, Mubarak said the direct talks should be preceded by discussions between the United States and the Jordanian-Palestinian delegation.

Peres reacted favorably to the proposal for direct talks but said he opposed any U.S. dialogue with the Jordanians and Palestinians that excluded Israel.

In the weeks since Mubarak made his proposals, intensive diplomatic contacts have continued, including a number of meetings here between Peres and U.S. Ambassador Samuel W. Lewis in which the possibility of a U.S. meeting with a Jordanian-Palestinian delegation was discussed. Peres was said to have displayed a "positive attitude" in the talks with Lewis without committing himself to any of the proposals.

Several factors appear to be at work in the low-key Israeli response to Reagan's suggestion of a change in the U.S. attitude toward meeting with a delegation that would represent Jordan and the Palestinians. Beyond their apparently contradictory statements, there is a cautious but clear desire by Peres and his senior aides to encourage moves toward reviving the peace process based on variations of the Mubarak proposals.

Toward that end, Peres has adopted a policy of refraining from strong criticism of almost any negotiating proposals short of suggestions that Israel or the United States talk to the PLO. But as the head of a divided "national unity government" that Peres' Labor Party formed with the right-wing Likud bloc headed by Shamir, the prime minister is walking a domestic political tightrope.