Survivors of the worse episode in this embattled country's warfare alleged today that government forces carried out a deliberate massacre of unarmed troops last month using aircraft and ground troops.

The charges were made by members of auxiliary forces loyal to the Rev. Ndabaningi Sithole, who nominally supports the black-led government of Prime Minister Abel Muzorewa.

Sithole called for the dismissal of Gen. Peter Walls, commander of the Zimbabwe-Rhodesian military forces, calling him a "trigger-happy general." Sithole also demanded that Parliament investigate the July 20 episode in which the government has admitted that 183 were killed.

Muzorewa, who is also the defense minister, denied the massacre charges in Parliament and provided the first detailed government version of the incident. He called the killings, which he said took place in two separate areas, a regrettable affair, and said they occurred after Sithole's irregulars refused to obey orders to lay down their weapons.

He said in the main incident at Gokwe, 150 miles west of Salisbury, government forces opened fire after the axuiliaries aimed their weapon at the troops.

"A firefight ensued, lasting some 45 minutes." Muzorewa added, resulting in 125 deaths.

The auxiliaries were formed by both Muzorewa's and Sithole's parties to support their election campaign earlier this year but since have become an arm of the security forces. The government has charged that they are "ill-disciplined" and often have committed crimes against civilians.

Several auxiliaries challenged Muzorewa's version, saying that no clash had occurred at Gokwe but rather that the government first used a ruse to disarm them and then opened fire from both the air and the ground.

Sithole said in an interview that the death toll at Gokwe alone was more than 300 with casualties still unknown from another occurrence at Nyamaropa near the Mozambique border. Muzorewa said 58 were killed there.

The impact of the allegations is likely to go well beyond the numbers. The reports come just three weeks before a scheduled all-parties conference in London to try to solve the 15-year-old Rhodesian independence issue and end the guerrilla war that has raged since 1972.

One of the main roadblocks to a peaceful settlement is the disposition of the rival military forces, with each side wanting control during a transition period leading to elections. Each side has accused the other of bruitality in the fighting that is killing more than 100 persons a day.

The alleged massacre came on the eve of the government's latest amnest program designed to persuade the guerrillas to come over to the Salisbury side. Four the the auxiliaries who escaped the killing said today that the alleged massacre had put an end to growing sentiment among some guerrillas to give up.

Speaking in Shona, Dipuka Nyaka, 27, said through an interpreter that the episode at the Gokwe base camp began early in the morning of July 20. He said the auxiliaries had completed some weapons training under the supervision of three white Army officers and then began instruction on working with support aircraft.

"The officers told us to put our arms on the ground because a government plane would soon fly overhead" and they should not make the pilot "nervous," he said.

"As the plane came over it opened fire" with machine guns and bombs, Nyaka added.

Next, security forces about 200 yards to the east encircled them and opened fire, according to Nyaka and Chinofamba Onyango, 24. They could not estimate how many ground forces were involved but did say they were mainly white and were brought to the area in 43 troop carriers.

They said they managed to flee through a mass of dust raised by the firing, running over the bodies of their companions.

"There was no shooting back and no chance to grab a rifle from the ground. You either escaped or died," Nyaka said.

The two said they hid in a cave for four days before walking 78 miles to a paved road, where they got a ride to Salisbury last weekend.

Two other auxiliaries, Biri Chimurenga, 21, and Furusa Mudzimu, 22, said their camp at Guamanya, about 10 miles away, was attacked by soldiers using five helicopters and four troop carriers. Only three were killed, however, because most had heard the earlier firing and fled the camp.

Firing by security forces in the Gokwe area continued for two days, they said.

In a separate interview, Komboni Muchecheteri, a farmer, said he was arrested by security forces and was forced along with several others to help pile the corpses into two trucks.He said he counted 160 bodies.

A distance away, he said."The soldiers had dug a big pit. The boies were thrown into it and then set on fire."