Rhodesian guerrilla leader Robert Mugabe said today that he thought President Carter was wavering from his "positive stand" of not recognizing the new government of Bishop Abel Muzorewa in Salisbury.

Speaking at a press conference here with his guerrila partner, Joshua Nkomo, Mugabe said that Carter "is apparently being forced to "move away from his decision not to lift economic sanctions against the Muzorewa government.

"You now have a position where the U.S. is drifting in the direction of Britian," said Mugabe, who is president of the Zimbabwe African National Union. Noting that Muzorewa recently met Carter at Camp David, Mugabe remarked that Carter "had no reason to meet a puppet and reactionary leader who lacks legitimacy."

British Prime Minister Margaret Thatcher has said her Consevative government will not fight to have economic sanctions reimposed on Zimbabwe-Rhodesia when they automatically lapse in November.

Mugabe's remarks accompanied speculation that the Organization of African Unity meeting here would recognize the guerrila alliance of Mugabe and Nkomo as the sole legitimate representative of the Zimbabwe people.

This would be the strongest endorsement yet of the guerilla alliance, known as the Patriotic Front, which is fighting to topple the moderate Muzorewa government. It would effectively preclude any open support among moderate black states for Muzorewa's government, which operates under a constitution leaving substantial political control in the hands of the white minority.

OAU recognition of the Patriotic Front as the only representative of the Zimbabwe people would also make it extremely difficult for Washington and London to recognize the current Muzorewa government.

Mugabe declared: "We look forward to a definite decision being taken by the OAU here supportive of the Patriotic Front as the only representative of the people of Zimbabwe; supportive also of our action of war against the regime in the interest of the people and for the purpose of bringing about complete decolonization of our country.

"Supportive therefore of our view that the regime in Salisbury must not be given any recognition."

There has been no disposition at the summit meeting to support Muzorewa's new government condemned by most black states as a fraud because of the political power retained by whites under constitutional guarantees that give them control of the army police and civil service and judiciary.

President William Tolbert of Liberia who is hosting the summit is an old friend of Muzorewa. Nevertheless he withdrew an invitation he had extended to Muzorewa's party to send a delegation to the conference apparently in deference to the widespread opinion among African states that Muzorewa should not be heard here.

Most sub-Saharan delegates appear to support the feelings of Nigerian head of state Olusegun Obasanjo, who told the heads of states Wednesday "We still consider that the Patriotic Front represents the true wishes of and aspirations of the majority of Africans inside and outside Zimbabwe."

Obasanjo attacked British moves to legalize and then recognize the Muzorewa government and said they "should be prepared to accept the full responsibility for the dire consequences of their actions."

The Nigerian leader also assailed pro-Salisbury sentiment in the U.S. Senate where he said "there is an astonishing degree of ignorance and deliberate misinformation about the realities of the African continent and the aspirations of the Africans." CAPTION: Picture, ROBERT MUGABE...hits Carter's meeting with rival