The Reagan administration is launching a major review of United States policy toward South Africa and is working closely with Britain in seeking ways to salvage a negotiated settlement to the intensifying racial conflict there, senior White House officials said today.

The policy review comes as the administration has grown increasingly frustrated with the intransigence of South African President Pieter W. Botha, who rejected President Reagan's appeals for restraint and declared a nationwide state of emergency June 12. More than 1,900 people have been killed since September 1984 in the turmoil over South Africa's policy of apartheid, or racial segregation.

The policy review also comes as a response to mounting pressure from Capitol Hill to impose new economic and political sanctions against Pretoria. The House earlier this month passed legislation calling for total U.S. disinvestment in South Africa.

While the legislation is given little chance in the Senate, White House officials said they realize that pressure is building there as well for stronger U.S. action. Senate Foreign Relations Committee Chairman Richard G. Lugar (R-Ind.) has scheduled hearings July 22.

Lugar and Sen. Nancy Landon Kassebaum (R-Kan.) have suggested that Reagan send a special envoy to South Africa, but the White House has rejected the idea for the time being. The senators also suggested the U.S. consult with Britain and West Germany on ways to begin talks between South African black and white leaders.

Officials said the policy review, being conducted by the National Security Council and the State Department, is not expected to result in new sanctions against South Africa, and that Reagan continues to resist such sanctions.

But the officials said it could produce expanded and more open contacts with black nationalist groups, including non-Marxist elements of the African National Congress (ANC), which South Africa and many conservatives in the United States regard as communist-dominated. Administration officials have said they have had regular contacts with some ANC leaders in the past.

A senior White House official said today one impetus for the policy review was the effort by a seven-member Commonwealth "Eminent Persons Group," which spent six months talking to all sides in South Africa, seeking to foster negotiations. The group concluded that Pretoria is "not interested in negotiating" and that a bloodbath of catastrophic proportions may be inevitable. The group called on the United States, Britain and West Germany to impose widespread economic sanctions against South Africa.

The group concluded that unless the West moves quickly against South Africa, a "radical" black government will emerge that "will destroy western interests absolutely" and will likely owe allegiance to the Soviet Union.

The White House official said the Commonwealth group gave up "too early" and that the administration, working with Britain, would like to pursue negotiations in a similar fashion. The official did not provide details except to raise the possibility of U.S. efforts to reach out to the black nationalist leaders in an effort to promote negotiations and forestall futher violence.

Although many of the 49 Commonwealth nations have already taken substantial measures against Pretoria, Britain, the most prominent member of the organization that includes most of its former colonies, has resisted sanctions on grounds that they are not effective.

Reagan has taken the same view, but imposed limited economic measures against Pretoria last year in an effort to head off stronger congressional action.

White House officials said the policy review is expected to be complete in the next few weeks. They said it probably will result in a National Security Decision Directive that would be presented to Reagan for his approval.

The officials said the review may produce a shift in emphasis away from Reagan's policy of "constructive engagement," in which the United States sought to use persuasion rather than punitive sanctions to bring about an end of apartheid.

Officials said they have become more pessimistic about events in South Africa since Botha imposed the nationwide state of emergency June 12, just before the 10th anniversary of the Soweto uprising. Since then, several thousand people have been detained and at least 66 killed as the violence continued. South Africa has also imposed heavy restrictions on the press.