Rhodesia's frail transitional government suffered another blow yesterday when Bishop Abel Muzorewa refused to join the other three government leaders on a trip to this all-black area, a visit that Prime Minister Ian Smith said was meant "to prove that we've now accepted majority rule."

Muzorewa declined to accompany Smith, Chief Jeremiah Chirau and the Rev. Ndabaningi Sithole because of their decision Tuesday not to reverse their dismissal of Byron Hove, a Muzorewa appointee as justice minister.

The bishop's absence yesterday increased fears that he will pull out of the biracial government formed by the four men in March. His party, the United African National Council, has threatened twice to do so unless Hove - who was fired for remarks advocating aggressive promotion and recruitment of blacks in the police and army - was reinstated.

Asked if he was disappointed that Muzorewa did not travel to Mrewa, Smith said, "Yes, I suppose so, we were supposed to come as four. He pulled out. It would be better with him . . . but we'll go on, nevermind, we'll go on."

The white prime minister, who has governed the rebel British colony since 1964, appeared dejected as he addressed a gathering of about 600 people in an open field of this tribal trust land reserved for blacks.

"We came so you can see for yourselves the truth of the facts, that we have made an agreement between the old Rhodesian government, of which I am a representative, and the new government, of which my colleagues are representatives," he said.

An empty blue chair announced the absence of Muzorewa. Sithole told the crowd: "We asked Mr. Smith to come so that he could demonstrate that he agrees to a transfer of power." Chirau explained how the agreement is to work.

The mostly rural blacks who stood or sat under the hot sun gave the three leaders a lukewarm response, possibly because of Muzorewa's absence. The bishop is thought to be the most popular figure among many Rhodesian nationalists, and this area of 95,000 blacks is considered one of his strongholds. He drew about the same number of people to a rally here Saturday.

"The people are saying, they are glad Muzorewa did not come," said an official of his party who was present. "They say these three are ganging up on the bishop," he said, refering to the Hove dispute.

The purpose of the trip was to give visibility to the black leaders in the transitional government and broadcast the coming of majority rule, schedule for the end of this year. The guerrillas who are fighting Rhodesia's security forces, were really the principal audience.

Last week the government offered amnesty to the guerrillas led by black nationalists Joshua Nkomo and Robert Mugabe who oppose the "internal settlement" reached by Smith and the three black leaders. Many Guerrillas operate in the Mrewa area and black residents said they were sure that "political commissars" of Mugabe's guerrilla army were mingling in the crowd.

Political and military observers in Rhodesia believe that the amnesty offer will not have enough success to permit the holding of elections for a government to run Rhodesia when it becomes the independent country of Zimbabwe - planned for Dec. 31.

Sithole appealed to the guerrillas, saying, "We must have a cease-fire for people to vote freely . . . We need the cooperation of the Rhodesian security forces and the guerrillas."

"Why do we go on fighting?" Smith asked.

Smith's address to the black audience was much like a teacher giving a history lesson as he condensed 13 years of Rhodesia's complex history to a simply put tale. His remarks were translated into Shona by a white aide.

"For a long time there has been trouble and argument in our country because the white people believed in a qualified franchise and the black people wanted majority rule.

"Unfortunately, the trouble grew and it got worse until there was war and the people were killing one another. What made things worse was that the communist countries decided they wanted to come into African countries . . . For this reason the big countries of the free world became concerned about the possibility of communist expansion here.

"Therefore they told me the time had come when I had to settle the dispute and stop the fighting. This is there reason which made my government and me change our minds.

"We changed, we accepted this thing called majority rule in order to help the free world bring peace to our country."

The leader of Rhodesia's 260,000 whites - there are 6.7 million blacks - then explained that the acceptance was conditional:

"I accepted majority rule providing that the black leaders accepted that we had to maintain conditions to retain the white man in Rhodesia."

The agreement has "entrenched" guarantees for whites of civil service pensions and provision for maintaining the army, police said judiciary much as they are today.

"It is important that under majority rule we ensure that Rhodesia does not degenerate into the kind of chaos and bad government which we know exists in such countries as Angola and Mozambique," he said.

There is no point in majority rule if that means there is going to be a breakdown of justice, of economics and if the country is not even able to produce enough food to feel itself."