While a storm of controversy surrounds the scheduled three-game American tour of the Springboks, the South African rugby team, other South African athletes have competed in the United States virtually unnoticed by groups opposed to South Africa's policy of racial separation, or apartheid.

Clubs in the North American Soccer League list 13 players claiming South African citizenship, and only last month South African boxer Gerrie Coetzee, who lost a world heavyweight title fight in 1979 to John Tate in Pretoria, fought in Tarrytown, N.Y., losing a split decision to American Renaldo Snipes.

For years, South African athletes have competed in Tournament Players Association golf tournaments in the United States, most notably Gary Player, three-time winner of the Masters Tournament, twice winner of the PGA Tournament and once winner of the U.S. Open.

South Africans also compete regularly in U.S. Tennis Association-sanctioned tournaments, and at least four other rugby teams from South Africa have played in the United States within the last year virtually without incident.

American supporters of the Springboks' tour, which they say is intended to promote rugby in the United States, argue that the Springboks are being singled out unfairly for special treatment.

"What's the difference between independent South African sportsmen like golf's Gary Player, tennis' Johan Kriek, boxing's Gerrie Coetzee . . . competing in the U.S. and a team of independent, nongovernment-controlled sportsmen playing here under the Springbok banner?" argued Ed Hagerty, editor of Rugby magazine, in a letter to Sports Illustrated.

The difference, contends Richard Lapchick, national chairperson of the American Coordinating Committee for Equality in Sports and Society (ACCESS), "is that the Springboks are a national team. This is the first national team from South Africa to come to the United States since the Davis Cup (tennis) team in 1978. There have been a few club teams since then, but this is the first national team. That's why they were singled out."

Since their exclusion from Olympic competition in 1970, South African athletes have been the targets of increasing pressure for isolation by the world sports community as a means of protesting apartheid. In 1978, four years after winning the Davis Cup, South Africa was thrown out of that competition, and in 1976 28 black African nations boycotted the Montreal Olympics in protest of the participation of New Zealand, which had previously played rugby with South Africa.

Last July, a Soviet soccer team, Donetsk Shakhtyor, refused to play against the NASL's Cosmos in the Trans-Atlantic Cup tournament in New York because of the presence on the Cosmos' roster of Steve Wegerle, a South African citizen. Earlier this year, four Soviet track athletes withdrew from the Millrose Games in New York because Sydney Maree, a South Africa native who has since renounced his South African citizenship and applied for American citizenship, was scheduled to compete.

The Soviets have reportedly said they will ask the International Olympic Committee to move the 1984 Summer Games in Los Angeles out of the United States if the Springbok games -- scheduled for Chicago, Albany and an undisclosed location in the Northeast -- are permitted to go on. The first match is set for Saturday in the Chicago area. A spokesman for New York Gov. Hugh Carey said Carey is looking into his authority to cancel the Albany game should he determine it to be a threat to public safety.