President Carter will interrupt his domestic policy summit at Camp David Wednesday afternoon to meet with Bishop Abel Muzorewa, the controversial black prime minister of Zimbabwe-Rhodesia whose election Carter has refused to recognize until now, informed U.S. sources said yesterday.

Muzorewa's claim to rule the breakway British colony in partnership with a white settler minority has been rejected by all of Black Africa. He arrived in Washington from London yesterday, declaring he was bringing "a bombshell of truth to all those who care to listen."

In another development that seemed to signal a growing flexibility in the administration's once firm rejection of the partnership between Muzorewa and former prime minister Ian Smith, a senior State Department official said the United States is considering allowing Muzorewa's government to assign a low-level diplomatic representative to Washington.

Carter decided last month to designate a junior U.S. diplomat as a special monitor of Muzorewa's progress toward majority rule. The administration may match this by allowing a Zimbabwe-Rhodesian here, but the official said this would not represent a formal exchange of diplomats.

The proposed meeting with Carter came under immediate attack from Randall Robinson, executive director of Transafrica, a U.S. black leadership group that lobbies on African issues. Saying he had been told of the Wednesday meeting by administration sources, Robinson urged Carter to cancel the meeting.

"It will encourage the bishop to be obstinate and give him a public relations lift even as his authority continues to erode in Zimbabwe" under the pressure of the guerrilla war conducted by the Patriotic front forces of Joshua Nkomo and Robert Mugabe, Robinson said.

The meeting "appears to be part of the administration's attempt to shut out the Patriotic Front by rehabilitating Bishop Muzorewa's regime that is recognized nowhere in the world," Robinson charged. "It approaches a diplomatic recognition of a regime that is unthinkably undemocratic."

The White House refused to confirm or deny that a meeting is scheduled. Other U.S. sources confirmed that, barring a last-minute change of mind, Carter would see Muzorewa at Camp David. Muzorewa also has bene invited to see Secretary of State Cyrus R. Vance this afternoon.

The U.S.-educated Mozorewa, a Methodist minister, said at Dulles Airport yesterday that he would argue during a spate of news interviews and congressional appearnces during his three-day stay that Carter's June 7 decision to maintain economic sanctions against Zimbabwe-Rhodesia should be overturned.

"It is only a sick person or people who still think they must maintain sanctions against a popularly elected government such as ours," said Muzorewa, whose party emerged as the largest in a new biracial Parliament formed after elections last April.

Muzorewa met last night with Sen. Jesse Helms, the conservative North Carolina Republican who has led the fight to force an end to the trade embargo that the Carter administration got Congress to reimpose in 1977. Helms is sponsoring Muzorewa's visit.

The United Nations and the British government imposed the embargo on international trade with Rhodesia after Smith's white settler government unilaterally declared independence in 1965. The United States participated in the trade ban until 1972, when it was lifted under the Nixon administration.

Richard Moose, the State Department's top Africa expert, said yesterday that Vance had written Muzorewa two or three weeks ago and offered to meet with the bishop during his Washington visit. Muzorewa had written after the April election asking to see the president.

"We feel that it is very important that Mr. Vance see him and talk to him," said Moose, who also confirmed that the State Department was considering allowing a Zimbabwe-Rhodesian diplomatic representative here. "We believe it is important to have the best possible communication."

In ruling last month against lifting sanctions, Carter and Vance sharply criticized the constitution under which the April election s were held. The constitution, approved by an all-white electorate, is viewed as entrenching white political control for at least the next decade. CAPTION: Picture, Zimbabwe-Rhodesian Prime Minister talks with Sen. Jesse Helmsn (R-N.C.) after arriving in Washington. AP