A commission appointed by Chief Gatsha Buthelezi, the most important black leader trying to end South Africa's system of strict segregation by peaceful means, has proposed making northeast Natal Province a racially integrated region as a model for the rest of the country.

The panel of 47 leading academics, businessmen and politicians warned that black opinion is swinging in favor of violence to overturn the system of apartheid, and that moderate leaders like Buthelezi must be seen achieving progress toward peaceful change to retain credibility among blacks.

The commission's report included results of detailed surveys showing 80 percent of blacks expressing deep discontent, and 75 percent of those under age 30 saying they have given up hope for peaceful change.

It urged merging white-run Natal Province with Buthelezi's tribal homeland of KwaZulu--an archipelago of land fragments scattered throughout Natal--to form a single, integrated area. The region would have autonomy like an American state with its own governor or chief minister and, if successful, could be copied elsewhere in the country.

First indications, however, were not promising for the plan.

In a major blow to the commission's hopes, the proposal was rejected by the leader of the party that controls Natal's governing council. Vause W. Raw of the mainly Natal-based New Republic Party said the plan would lead to racial conflict.

The ruling National Party of Prime Minister Pieter W. Botha also said that the commission's plan was unacceptable, a South African Embassy spokesman in Washington said.

A statement by Finance Minister Owen Horwood, who is also the party's leader in Natal, said that a "unitary society" in the province would clash with government policy, the spokesman said.

Buthelezi, head of the 6 million-strong Zulu tribe, is a paradoxical figure in South African politics. Though chief minister of KwaZulu, he has led the way in rejecting the government's plan to give independence to it and the nine other tribal homelands. The plan would deprive the nation's blacks of South African citizenship.

Buthelezi also has mobilized the largest black political organization ever to have existed in South Africa. Called Inkatha, it claims 350,000 paying members.

His commission, set up in 1980, presented its report last weekend. It made clear the proposals did not constitute an ideal plan, but one that is a "realistic possibility" in terms of government policy and could at least "open the way to further progress."

As a first step, the commission said there should be negotiations between the Natal provincial executive and the KwaZulu executive to amalgamate. The talks would include the province's Asians and other minorities.

Elections for a new regional legislature would follow, under rules assuring representation for minorities.

Because 70 percent of the population of the combined region is African, the majority in the legislature clearly would be black and Buthelezi would be the chief minister.

However, the commission said its opinion surveys indicated a majority of whites, Africans, Coloreds (persons of mixed race) and Asians in the region would favor the plan.

Minorities would also be protected by a bill of rights and by a minority veto on basic matters such as education. The chief minister would choose a Cabinet "in balanced or appropriate numbers of the various groups in the assembly."

The panel's surveys showed a majority of blacks expressing support for the outlawed African National Congress--which is committed to overthrowing white-minority rule by guerrilla warfare--except in Natal, where Buthelezi and Inkatha headed the poll.

In 1977, a similar set of surveys conducted by a West German research institute gave Buthelezi 42 percent support and the African National Congress 17 percent support in the Witwatersrand, South Africa's biggest metropolitan area. The commission found these percentages reversed today.

"While a revolutionary situation has not yet emerged in general terms, developments point in that direction," the commission concluded.

The commission said most blacks polled expressed the view that the majority of the black population would cooperate with African National Congress insurgents. Seventy percent predicted mass strikes by Africans if called by a credible leader.

Among white politicians, the plan was welcomed by Frederik Van Zyl Slabbert, leader of the integrationist Progressive Federal Party, which is the official opposition in the South African Parliament and has growing support in Natal.

He said he found it a "very hopeful sign" that there were still black leaders like Buthelezi prepared to think in terms of peaceful change by constitutional means. Slabbert warned that if the government ignored Buthelezi's initiative, "it will be at the peril of us all."

Government policy is to give independence to the tribal homelands, which together constitute 13 percent of South Africa's land area.

As each gets independence, Africans of that tribe automatically forfeit their South African citizenship and become citizens of the homeland only.

When all the homelands are independent, there will no longer be any black South African citizens. All will be foreigners with no claim to political rights.

Buthelezi is spiking the plan by refusing to accept independence for his Zulus, South Africa's largest and most famous tribe. Following his example, five other homeland leaders so far also have refused independence. Four have accepted.

Although vilified by radicals for working within the system, Buthelezi is turning his homeland into a base for opposing government policy.