Robert S. Strauss said yesterday that he was seeking to step out of his formal diplomatic role as special Mideast ambassador into a similar but unpaid job that would leave him more time to devote to his personal life.

Strauss, in an interview on "Face the Nation" (CBS, WDVM) said he had consulted with Secretary of State Cyrus R. Vance and other top administration officials about his possible changeover to so-called "dollar-a-year" status. Such a shift would leave him without his formal ambassador-at-large title but still actively involved in the Middle East negotiations, he said.

Under the dollar-a-year provision Strauss would be limited to 130 government workdays a year. He has said such a time limit would still allow him to continue to devote full attention to his primary task of negotiating a settlement of the Palestinian autonomy issue.

Strauss was appointed by Carter to the ambassador-at-large post last April. Although no action has been taken on getting congressional approval of the appointment, he has been hard at work since then on the Palestinian issue. Strauss said yesterday he had not talked with the president about his desire to shift to unpaid status.

"I want a semblance of a personal life," said Strauss, 60, who has been chairman of the Democratic National Committee and Carter's special trade envoy in the past. "I would like to have a bit more time for private life."

He added, however, that if the president approved the change in status he probably would avoid any association with his old Texas law firm of Akin, Gump, Hauer and Feld. The firm, which Strauss helped to form, has oil interests among its clients.

Strauss' role as Mideast negotiator touched off a flap last week when he told reporters he disagreed with the administrations' latest proposal to establish a compromise U.N. position on the Palestinian question.

The special envoy made his feelings known after the proposal was rejected by both the Israelis and the Egyptians during Strauss' latest Mideast tour.

Yesterday, however, he sought to soften his earlier criticism, saying that the rejected proposal was only one of "a pocketful of suggestions" he was carrying on his latest mission.

Strauss said he proposed 10 to 15 possible positions on the Palestinian question but none of them received much support.

Strauss, who is expected to leave on another Mideast diplomatic mission after Labor Day, said he planned to confer with State Department officials today on violence between Israeli-backed militia and Palestinian forces in southern Lebanon.

He said the United States should undertake a "diplomatic offensive" to halt the fighting between the two groups. A U.N. spokesman announced in Beirut yesterday that a cease-fire between the militia and the Palestinians was in force after four days of artillery dueling.