An inquest court in the South African tribal homeland of Venda, officially regarded here as an independent country, found yesterday that two security policemen had beaten a Lutheran preacher to death while interrogating him.

The preacher, Tshifhiwa Muofhe, died last Nov. 12 when security police in the homeland made extensive arrests following an attack by African National Congress insurgents on a police station in the main town of Sibasa, killing a policeman.

Detained with Muofhe were three other pastors of the Lutheran Church and their dean, Simon Farisani.

Muofhe was found dead in his cell the day after his detention. Farisani was seen in a hospital a few weeks later, badly bruised and in chains. The families of the other pastors said they were tortured.

The U.S. National Committee of the Lutheran World Federation issued a strongly worded protest at the time through its general secretary, Paul A. Wee, and Amnesty International began an investigation.

The Venda authorities rejected these protests and denied the allegations of assault and torture. Two clergymen who helped Muofhe's widow were deported. The Lutheran bishop for the area, Solomon Serote, was refused entry to the homeland to conduct Muofhe's funeral.

The security police continued to hold the pastors and their dean for months without charges. Eventually two were charged with murdering the policeman, but both were acquitted June 1 after a brief trial.

Now, after a delay of more than seven months, an inquest into Muofhe's death has been held. Magistrate Stanley Stainer found that Muofhe's two interrogators, Capt. Muthupphei Ramaligela and Sgt. Phumula Mangaga, had beaten him to death.

Three doctors agreed Muofhe had died from severe bruising of the body, including his head and genitals, and internal bleeding.

The government's local district surgeon, Manfred Teichler, said death had been caused by "extensive use of blunt force." Two senior pathologists agreed. One said he found "10 instances of directed violence" to Muofhe's back.

The interrogators claimed Muofhe had confessed, then, while accompanying them to a spot in the mountains at night, had tried to escape by jumping off the back of a truck, sustaining the injuries described by the doctors. Their version collapsed when the lawyer for Muofhe's family, Ernest Wentzel, was able to show that the truck they claimed to have used was out of service at the time.

The inquest record will now go to the attorney general of Venda, who must decide whether to charge the two security policemen with murder.

The other Lutheran pastors have been released from detention, six months of which Farisani spent in the hospital. Their church has given them "recuperative leave."

Venda is one of 10 tribal homelands demarcated by the South African government as areas where the country's 21 million Africans can exercise political self-determination, while the 4.5 million whites remain in political control of the other 87 percent of South Africa.

African nationalists are strongly opposed to the homelands policy, which they see as a means of continuing black oppression. They denounce Africans who participate in the system as quislings.

Venda was granted nominal independence in 1978 under the presidency of a semiliterate clan chieftain, Patrick Mphephu. The homeland covers 2,300 square miles, about the size of Delaware, and is tucked away in the northeast corner of South Africa, near the borders of Mozambique and Zimbabwe.

Both those black-ruled countries support the outlawed African National Congress, the main black nationalist movement in South Africa, which is trying to overthrow white rule by guerrilla action. This means Venda is vulnerably situated, which accounts for the jumpiness of its tribal authorities after the police station attack.