Members of Congress were told in private yesterday that the Carter administration plans to resume negotiations on a new Panama Canal treaty the week after the inauguration, and expects to complete the new pact by June.

President-elect Jimmy Carter said he is thinking of going to the nation with a fireside chat broadcast to build support for the new treaty.

Dispute over giving Panama greater rights over the canal was an emotional issue during the presidential election campaign. President Ford and Carter both took a firm line on retaining U.S. control of the canal in the campaign. Nevertheless, the treaty being negotiated is certain to make concessions to Panama, in a dispute which is a symbolic test of American policy for all Latin America.

The Carter administration's plans wer disclosed at a unique, all-day seminar on foreign policy with about 50 members of Congress, including Republican and Democratic leaders, at "The Castle" of the Smithsonian Institution.

Secretary of State-designate Cyrus R. Vance told the group that Panamanian Foreign Minister Aquilino Boyd will arrive here the week after the inaugural for the Panama Canal negotiations. Veteran U.S. negotiator Ellsworth Bunker has said he believes the negotiations can be completed by June, Vance said.

Sources said that when House Republican Leader John J. Rhoes (Ariz.) cautioned that the public must be prepared to accept a new canal treaty. Carter mentioned a fireside chat. Rep. Clement J. Zablocki (D-Wis.), senior Democrat on the House International Relations Committee, suggested a special need to solicit support among the military and veterans for a new treaty.

Carter told reporters that the meeting yesterday also produced agreement that there are prospects for "dramatic improvements in the Middle East."

He said "the moderation of Arab leaders" in recent statements, coupled with Israel's yearning for peace, "all give us hope that we might have substantial achievements" in new Arab-Israeli negotiations.

The most significant aspect of Carter's full-day meeting with members of Congress and his top national security staff members was the gathering itself, to signify a new page in executive-congressional relations.

Carter described the conference on foreign policy and economics as "the beginning of an interrelationship that might bring us together." It was hailed on all sides and Carter said when the session ended just after 5 p.m., "I'm very pleased with the outcome . . ."

Sen. Hubert H. Humphrey (D-Minn.) lauded it as an unprecedented, preinaugural, "free-flowing exchange" of views. Senate Republican Leader Howard H. Baker Jr. (Tenn.) said he told Carter there are bound to be disagremeents, in the four years ahead, but he commended the effort to minimize disputes and also praised "Carter's depth of knowledge" on the issues.

Clifford P. Chase (N.J.), ranking Republican on the Senate Foreign Relations Committee, said the meeting was "a political operation" and "a good idea" which should be repeated, to prevent "an elite staff operation" from isolating the President.

Sen. Frank Church (D-Idaho) said the session epitomized taking "our advice" as well as the more customary demand for "our consent." To Sen. Charles H. Percy (R-Ill.) the meeting was "a giant step forward" in congressional-executive relations.

Sen. Jacob K. Javits (R-N.Y.) called it "an auspisious start," as did Sen. Claiborne Pell (D-R.I.) and others.

Topics reviewed during the day ranged from U.S.-Soviet nuclear arms control negotiations to Carter's plans for "a much more cohesive and comprehensive policy on economics." Participants said there was no attempt to establish a position on each subject, but rather to exchange viewpoints.