In a statement issued shortly after yesterday's vote, Reagan promised to uphold the law despite his objections to it, but warned that "this will not solve the serious problems that plague that country."
The number of senators voting to override was 12 more than the two-thirds needed. Thirty-one of the 53 Republicans joined all 47 Democrats in voting to override. All senators from the Philadelphia area voted to override the veto.
One senator, Jake Garn (R., Utah), who is recovering from surgery, did not vote.
Despite a week-long lobbying effort, Reagan won the votes of only six of 37 GOP senators who voted for the bill when it first passed the Senate on Aug. 15. Those who switched were Thad Cochran of Mississippi, Robert Dole of Kansas, Orrin G. Hatch of Utah, Don Nickles of Oklahoma, Alan K. Simpson of Wyoming and Ted Stevens of Alaska.
However, one senator who voted against sanctions, Larry Pressler (R., S.D.), suggested that several GOP senators would have been prepared to vote with Reagan to sustain the veto had the vote been closer.
Reagan also won the vote of Sen. Barry Goldwater (R., Ariz.), one of two senators who did not vote in August. But the other, Sen. Frank H. Murkowski (R., Alaska), voted against Reagan yesterday.
The bill, which becomes law immediately, bans most new U.S. investment in South Africa, terminates U.S. landing rights for South African Airways and bars imports of South African coal, iron, steel, uranium, textiles and agricultural products.
It also makes permanent four sanctions that Reagan reluctantly imposed by executive order last year under heavy congressional pressure. They ban new bank loans to the South African government, computer sales to government agencies that enforce South Africa's racial-segregation policy of apartheid, imports of krugerrand gold coins and any nuclear cooperation between the two countries.
The sanctions, which take effect within 90 days, could be terminated or modified if the South African government does at least four of the following:
* Frees jailed black leader Nelson Mandela and other political prisoners.
* Repeals the nationwide state of emergency proclaimed by the government in June.
* Legalizes several banned opposition political parties.
* Repeals laws restricting where blacks can work and live.
* Enters into negotiations with representative black leaders on the country's political future.
The freeing of Mandela must be one of the four actions taken before the sanctions can be lifted or modified, according to the measure.
The bill also permits the president to impose additional sanctions within one year's time unless Pretoria has made significant strides in phasing out apartheid.
The Senate vote represented a final and overwhelming congressional rejection of Reagan's conciliatory policy, called "constructive engagement," which has sought unsuccessfully to wean South African whites away from apartheid through quiet persuasion rather than public condemnation and sanctions.
Reagan vetoed the sanctions bill last Friday, saying it would harm South African blacks the most. Two days later he vowed to sign a new executive order imposing a limited set of sanctions if Congress upheld his veto. He made phone calls to several GOP senators during the week and sent Secretary of State George P. Shultz to Capitol Hill on Tuesday in an effort to hold the line.
But the mounting violence, repression and racial turmoil in South Africa in recent months have caused a steady erosion of congressional support for Reagan's policy and, in the end, led all but the most conservative lawmakers to desert him.
The final blow came on Wednesday, when South African Foreign Minister Roelof F. "Pik" Botha telephoned four senators and threatened to cut off South African purchases of American grain if the veto were overridden.
Several senators denounced Botha's threat on the floor yesterday. Sen. Edward M. Kennedy (D., Mass.) called it a "blatant attempt to influence the foreign policy of this country" and said the Senate would not yield to ''threats of retaliation by bullies whose policies we abhor."
But another sanctions supporter, Sen. Lowell P. Weicker Jr. (R., Conn.), said Botha's ploy had no effect on the Senate vote. "The United States Senate had made up its mind. This issue was resolved long before today," he said.
Sitting in the Senate visitors gallery during the vote were several luminaries of the civil rights movement, including Coretta Scott King, Martin Luther King 3d, Dick Gregory and Randall Robinson.
"I believe that today Martin Luther King's dream has been advanced," Mrs. King said. "He said many times that apartheid was the worst form of institutionalized racism in the world. That form has been dealt a death blow today."
With them in the gallery were several of the unheralded activists who had brought the South Africa issue to national attention by staging a daily, year- long protest campaign outside the South African Embassy last year.
"I'm just thinking right now about how cold my feet were on those picket lines," said Cecily Counts as she watched the voting. "Today makes it all
Here is the roll-call vote:
Democrats voting to override:
Baucus, Mont.; Bentsen, Texas; Biden, Del.; Bingaman, N.M.; Boren, Okla.; Bradley, N.J.; Bumpers, Ark.; Burdick, N.D.; Byrd, W.Va.; Chiles, Fla.; Cranston, Calif.; DeConcini, Ariz.; Dixon, Ill.; Dodd, Conn.; Eagleton, Mo.; Exon, Neb.; Ford, Ky.; Glenn, Ohio; Gore, Tenn.; Harkin, Iowa; Hart, Colo.; Heflin, Ala.; Hollings, S.C.; Inouye, Hawaii; Johnston, La.; Kennedy, Mass.; Kerry, Mass.; Lautenberg, N.J.; Leahy, Vt.; Levin, Mich.; Long, La.; Matsunaga, Hawaii; Melcher, Mont.; Metzenbaum, Ohio; Mitchell, Maine; Moynihan, N.Y.; Nunn, Ga.; Pell, R.I.; Proxmire, Wis.; Pryor, Ark.; Riegle, Mich.; Rockefeller, W.Va.; Sarbanes, Md.; Sasser, Tenn.; Simon, Ill.; Stennis, Miss.; Zorinsky, Neb.
Republicans voting to override:
Abdnor, S.D.; Andrews, N.D.; Boschwitz, Minn.; Chafee, R.I.; Cohen, Maine; D'Amato, N.Y.; Danforth, Mo.; Domenici, N.M.; Durenberger, Minn.; Evans, Wash; Gorton, Wash.; Grassley, Iowa; Hatfield, Ore.; Hawkins, Fla.; Heinz, Pa.; Kassebaum, Kan.; Kasten, Wis.; Lugar, Ind.; Mathias, Md.; Mattingly, Ga.; McConnell, Ky.; Murkowski, Alaska; Packwood, Ore.; Quayle, Ind.; Roth, Del.; Specter, Pa.; Stafford, Vt.; Trible, Va.; Warner, Va.; Weicker, Conn.; Wilson, Calif.
Republicans voting to sustain the veto:
Armstrong, Colo.; Broyhill, N.C.; Cochran, Miss.; Denton, Ala.; Dole, Kan.; Goldwater, Ariz.; Gramm, Texas; Hatch, Utah; Hecht, Nev.; Helms, N.C.; Humphrey, N.H.; Laxalt, Nev.; McClure, Idaho; Nickles, Okla.; Pressler, S.D.; Rudman, N.H.; Simpson, Wyo.; Stevens, Alaska; Symms, Idaho; Thurmond, S.C.;
Not voting: Garn (R., Utah).