Prime Minister Abel Muzorewa indicated tonight that his new government will vigorously seek international recognition and will only work with its guerrilla opponents if they accept him as the country's leader.

Muzorewa's stand makes it unlikely that there will be a conference of all the factions in the civil war here. Such a meeting had been urged by Britian and the United States as the only way an accommodation could be reached between the Soviet-backed guerrillas and the black majority government that has just assumed office here.

In his first major policy statement since he became prime minister Friday, Muzorewa issued an invitation to the leaders of the guerrilla movement, Joshua Nkomo and Robert Mugabe, to end the war and come home in the spirit of reconciliation.

He called his amnesty offer a "genuine . . . effort to achieve reconciliation . . . from the bottom of our hearts."

"We accept our opponents as long as they are a responsible oppostion," he added.

Nkomo and Mugabe, who are based in neighboring Zambia and Mozambique, say that Muzorewa's government is a sham because whites continue to control such vital areas as the Army, police, judiciary and civil service.

The two men rejected an amnesty similar to that offered today by Muzorewa just after the establishment of the biracial transitional government in April. They went on to intensify their activities. Only a handful of the estimated 12,000 guerrillas took up that amnesty. Although military authorities claim that more and more rebels are accepting it in recent months, no proof of this has been offered to journalists.

Tonight's amnesty offer comes as satistics show that the death toll in the country's 6 1/2-year-old guerrilla war set a record in May with 891 dead. In April 842 people died, according to reports.

According to official sources, Muzorewa conferred during the week with Allard Lowenstein, an adviser on Africa to the U.S. State Department. In addition, the sources said, "a number of other figures connected with the Carter administration" have visited Salisbury in recent days.The United States has said its policy toward Zimbabwe Rhodesia is under review following the April elections that put Muzorewa in office.

Secretary of State Cyrus Vance told reporters Saturday that Lowenstein did not go to Salisbury in any official capacity.

Muzorewa said tonight that the amnesty offer was "only one side of our peace plan."

"The other is that we will defend ourselves, our sovereignty, our democracy and our land against any form of aggression," the bishop added.

He said that "a number" of Mozambican soldiers recently were killed or captured inside Rhodesia, suggesting a growing involvement on the part of Mozambican troops with Mugabe's guerrillas.

Muzorewa appealed to Mozambique's President Samora Machel, "in the name of humanity and good neighborliness . . . please review any decision that might have been taken to become involved in our domestic affairs."

Well-informed sources said authorities here have been aware of activity by Mozambique's troops inside the country for some time. It is believed they help Mugabe's guerrillas mine roads, especially around border towns. One Mozambique soldier was shot inside Rhodesia almost four months ago, one source said.

Muzorewa said tonight that he sent messages to Machel and to Zambian President Kenneth Kaunda asking them to stop providing sanctuary to the guerrillas because "the reasons for the war no longer exist."

Muzorewa siad that a month had passed since then. "I take as a negative reply the fact that they are still allowing their countries to be used as bases to fight to overthrow our democratically and popularly elected government. The nation is entitled to know this.

Muzorewa appealed to the United Nations and Britian to recognize his government and lift sanctions imposed by the United Nations 13 years ago in a move designed to punish the white minority government that had broken away from Britian.

Muzorewa said he has already sent envoys to "various countries in Africa."

No details of the diplomatic offensive were given except that the envoys were sent after last month's elections. Presumably they are arguing that the changes in Zimbabwe Rhodesta represent a genuine transfer of power to the black majority despite the powers still assigned to the white minority. CAPTION: Picture, PRIME MINISTER MUZOREWA . . . proposes a conditional amnesty