CAPE TOWN, SOUTH AFRICA, SEPT. 17 -- A presidential commission today recommended cautious but significant changes in apartheid laws that rigidly segregate residential areas in South Africa by race, proposing that communities be given the option to open themselves to all races.

The recommendations, prepared over three years by a constitutional committee of the advisory President's Council, provide numerous doors that can still be shut on blacks seeking to move into white areas, virtually guaranteeing that most of South Africa will remain segregated.

But if approved by the government and Parliament, the proposed changes to the 1953 Group Areas Act would for the first time remove statutory barriers to housing integration. It could also make possible nonracial voting on the local level and even integrated schools if mixed communities wanted them.

The commission acknowledged that the practical effect of the proposed reforms would probably be to open up affluent, all-white suburbs to those nonwhites who can afford them, while blue-collar communities are likely to exercise the option to remain racially segregated.

The proposals would also integrate all business districts in South Africa and scrap the 34-year-old apartheid law that designates segregated facilities, such as beaches, on a nationwide basis. However, local governments and the owners of privately owned facilities would be allowed to discriminate by race.

Initial reaction by leaders of South Africa's 85 percent nonwhite majority was critical, and was accompanied by demands that the Group Areas Act be thrown out in its entirety.

Only one of the four nonwhites on the 17-member constitutional committee, T.L. Gounden, an Indian, signed the 150-page report, and that was with the notation that he opposes the principle of the Group Areas Act but believes that the recommendations will lead to its repeal.

The chairman of the committee, Andries Oosthuizen, said in a briefing of reporters that the underlying principle of the proposals was that no community should be integrated against the will of its residents. But at the same time, he said, neighborhoods that want to change their character through integration should not be barred from doing so.

Oosthuizen said, "You need to have an appreciation for a historic situation that has developed over the centuries. By totally uprooting this immediately, I think you're looking for trouble and insecurity."

President Pieter W. Botha has repeatedly declared his support for segregated communities and schools as guarantees of cultural values. A statement released by the state Bureau for Information on behalf of his office said the Group Areas Act, like any other law, is subject to amendment.

It added that while the government stands behind the principle that group rights must be protected, "it must also be possible to make provision for those who prefer a different lifestyle."

Government sources noted that Botha last year held up the release of a previous draft of the report because it did not deal adequately with the implications for voting rights in integrated communities.

The sources left the impression that today's recommendations would not have been released if there had been strong objections by Botha and his Cabinet.

Oosthuizen told reporters that once the recommendations are approved by the government, they could go into effect within six months.

The proposals provide two ways that blacks, those of mixed-race, known as Coloreds, and Indians can move out of their designated residential areas into other communities.

An individual black, for example, could apply for what in effect would be a zoning variance to move into a community designated for whites only. His request would be advertised and petitions, hearings and, in some cases, a referendum would follow.

Based on the consensus of the community, the local government would decide whether to grant permission. The system would replace the current practice of appealing to the central government for an exception permit to move into an area designated for people of another race.

Similarly, existing segregated communities could seek to change their status to "open" through the consensus procedure, and the developers of new housing projects could seek "open" status, subject to review and possible veto by the provincial administration.

The racial status of land in a community would be recorded on the title deed of houses, which could then be sold only to the permitted racial groups.

If a request to create a mixed neighborhood were turned down either by the local government or the provincial administration, a new application could not be submitted for two years.

One senior government official said that consideration was being given to a proposal -- not included in the report -- that would allow communities to place a percentage quota on the extent of integration.

Oosthuizen said that the provision for veto at the provincial level was designed to protect communities adjacent to residential areas that may opt for integration.

The chairman said that the "local option" formula was devised with the aim of protecting lower-income and elderly residents who would be unable to move out of a changing neighborhood.

The committee said in its report that any new legislation would have to deal with the reform's implications for voting rights at the local level.

"There can be no justification for two people living next door to each other to use the same services, and pay rates and taxes, and for one to have a say in the provision of services by voting for a representative, while the other has no say," the committee declared.

The report listed five options for the central government to consider: common voting rolls open to all; open voting rolls but with candidates restricted to the same color as the existing local government; leaving the decision to the local authority; separate voting rolls with separate governing boards, and no voting rights for those who integrate a newly opened residential area.