Rhodesian guerrilla leader Robert Mugabe said here today that many of his troops were not coming out of the bush in Rhodesia, despite the deadline at midnight, because of a continued presence of South African and Rhodesian auxiliary forces in the country.

However, British officials in Salisbury expressed gratification at the turnout and said it had reached 12,000 of what they say are about 16,000 guerrillas in Rhodesia.

In an interview Mugabe accused Britain of failing to implement the cease-fire agreement in an impartial manner. He also defended the decision of his Zimbabwe African National Union to run separately from its Patriotic Front partner, the Zimbabwe African People's Union in the upcoming elections and said he was confident of victory.

"One reason why our people are not eager to get to the assembly points is because of the presence of the auxiliary forces," belonging to former prime minister Abel Muzorewa, said Mugabe. "The understanding was always that the Rhodesian forces, including the auxiliaries, must first disengage and only after that will our forces move to the assembly points. This has not happened, so why should the British expect that our forces will move?"

Mugabe estimated that there are still more than 20,000 of his guerrillas outside the assembly points.

In Salisbury, however, a British Commonwealth source said just before the midnight deadline that the guerrillas' turnout was a "remarkable achievement."

According to news service reports, British officials estimated that about 9,000 had assembled by early today, with the flow in the last 24 hours far surpassing that earlier reported. The British and Mugabe have differed consistently on the estimates of guerrilla strength.

Mugabe said that according to reports from his commanders in the field, Muzorewa's auxiliary forces have moved into villages and other areas as soon as the Patriotic Front forces moved out to assembly points. "Nobody is complaining that the Rhodesian forces are not all in their barracks. The auxiliaries are still everywhere. They are not assembling," Mugabe said.

The ZANU leader accused Britain of further violating the cease-fire accords by "inviting in" South African troops. He contended that "upwards of three of four battalions" of South African troops are now in Rhodesia and that "20 truckloads of South African troops have moved into the country in the last two days or so."

"This is a violation of the cease-fire agreement. In these circumstances our forces have no duty at all to move," Mugabe said.

The presence of South African troops demonstrates "the dishonest manner in which Britain has handled the cease-fire," he said. "The British had told us that as soon as the governor set foot in Salisbury, any foreign troops, including South African ones, would go. But now it appears that these troops have come into the country at the invitation of Britain.

"Britain's strategy seems to be that eventually South African troops will surround us and encircle us. Once elections are held and the people vote us into the government," he added, "britain will leave the country and we will be face to face with the South Africans. And in these circumstances South Africa can easily move to surround our forces confined in the assembly points." Mugabe said he protested yesterday to the British ambassador here.

Commenting on ZANU's decision to divide the Patriotic Front in the upcoming elections, Mugabe asked, "Why shouldn't we? We've never been one party. We've been a front composed of two components. We have our own policy as ZANU, our own organs, our own supporters and our own army."

He explained that the elections would for the first time decide democratically the relative strength of the two parties and the question of leadership. "As a front, we have said we are equal. But when we go into a government and if we form a coalition, it will have to be decided not on the basis of equality but on the basis of support that the people have given us."

Mugabe continued that although he and Nkomo have shared leadership of the front, "we cannot now have a dual premiership. If the people decide that ZAPU is stronger, then they have it. If they decide that ZANU is stronger, then we have it."

He went on to deny that Muzorewa would be given a position in a ZANU-led coalition."If he has lost, he has lost. If the people discard him then let God take him back because that's where he belongs."