ROBBEN ISLAND, South Africa— South Africans managed to overcome their vast cultural and political differences as they created their new Government, but a dry, windswept island six miles across the water from Cape Town is putting into focus the debate that is yet to come over how to treat the country's history.

Robben Island has been the home of South Africa's unwanted: lepers, the mentally disturbed, political prisoners, criminals. Now, the new Government is trying to decide what to do with the spot of land that for years served as President Nelson Mandela's jail.

The previous Government had developed plans to close the island's two prisons, which currently hold about 700 convicted criminals, at the end of 1996. The new Government has yet to decide about the island's future.

Different interests have put forward their own visions for the island. Some environmentalists want to return it to a pristine state as a wildlife refuge. A land developer made a proposal to build a casino there. Some want to turn it into a museum, and one group would like to set up a center to teach nonviolent conflict resolution.

But the new minister of the Department of Correctional Services says that given the overcrowding in South Africa's prisons, he may push to keep the island as a penal colony.

"It needs to be remembered, but the question is in what form," said Felicia Siebritz, the administrator of the Mayibuye Center, a center for black history at the University of the Western Cape.

Drawn by the mystique of the island where Mr. Mandela spent 18 of his 27 years in prison, sightseers are already flocking there. Tours that are offered three days a week by the Department of Correctional Services are booked solid for the rest of the year.

"This place not only symbolizes the evil of apartheid, but also the strength of the human spirit," Michael Lapsley, an Anglican priest and anti-apartheid advocate, said on a recent visit.

Though Mr. Lapsley was never imprisoned on the island, his life was also seared by the brutal repression of dissidents that Robben Island symbolizes. In April 1990 he lost both of his hands when a letter bomb sent to his house in Zimbabwe exploded.

The interest in Robben Island has led to concerns that it will be turned into some crass commercial venture. Sol Kerzner, developer of the glitzy Sun City resort north of Johannesburg, expressed interest in building a casino. Prison officials said he was turned down.

"What do we need a casino here for?" said Col. Hennie de Beers, the prison warden. "We have enough casinos on the mainland."

The tours touch only briefly on what made the island famous: its use as South Africa's Bastille.

Security concerns preclude visitors from seeing the insides of the two prisons or Mr. Mandela's tiny cell. The soft sandy road that leads to the limestone quarry where political prisoners labored under the glaring sun -- and surreptitiously spirited messages to each other -- cannot accommodate the tour buses.

The island has no exhibits showing the daily life of the prisoners. Until a few years ago, jailers segregated the prisoners by race and maintained a rigid racial caste system. For example, white inmates were given seven ounces of meat, 16 ounces of vegetables and two cups of coffee a day, according to records gathered by the Mayibuye Center. But black prisoners only got five ounces of meat and one cup of coffee.

For years, the black prisoners were denied sweaters and long pants despite the cold, rainy winters here.

Still, prisoners were able to scratch out a semblance of normal life. They even organized a rugby league. "In the early 60's life was very, very harsh on the island," Ms. Siebritz said. "But in the 70's after protests from the prisoners, things loosened up."

The damage from a series of riots in prisons across South Africa this month -- but not here -- could delay the closing of the prisons here, Colonel de Beers said.

The tours show only the outside of the slate-gray prison compounds, the church used when Robben Island was a leper colony from 1845 to 1931, the three World War II gun batteries painted in green and black camouflage, and the springboks, ostriches and penguins that inhabit a wildlife refuge.

A group of peace advocates, Peace Visions, has another idea for the island. It has begun lobbying the new Government to establish a training center there in human rights law and conflict resolution.

The group already conducts workshops there for high school students of various ethnic backgrounds from the Western Cape to teach them how to defuse racial conflicts in their schools.

"The question is whether Robben Island becomes a shrine to the past -- just a museum with old relics -- or something that has practical application for today," said Terry Crawford-Brown, director of Peace Visions.

Henry Fazzi, 70, wants to see a museum there. He is a former commander in the African National Congress' military wing, Spear of the Nation, and was imprisoned on the island for 20 years.

"The island is important not only to us in South Africa, but for everybody in the world," he said. "I was in America in 1991. I went everywhere from the South to the North, and everybody knew about Robben Island."

Photo: South Africa is trying to decide what to do with its best-known prison, Robben Island, near Cape Town. Passengers disembarked from a ferry before beginning a tour of the island, as guards watched. (Guy Tillim for The New York Times) (pg. A4) Map shows the location of Robben Island.