Following the lead of musicians who joined voices to help the hungry in "We Are the World," more than 50 top pop stars have banded together to encourage a cultural boycott in "Sun City," a song attacking South Africa's system of apartheid.

Radio stations received the "Sun City" single today, and copies should be in record stores by Friday.

The artist roster includes Little Steven Van Zandt -- who wrote the song and organized the project -- Bruce Springsteen, Bob Geldof, Bono of U2, Run-DMC, Hall and Oates, Miles Davis, Bob Dylan and producer Arthur Baker. All donated their time and talents to the song, which uses Sun City, a Las Vegas-style luxury entertainment complex in Bophuthatswana, as a symbol for South Africa's oppressive racial policies.

The "Sun City" project, which was originally envisioned as only a single, has since blossomed into a full album, scheduled for release a week from Friday.

With its chorus of "I ain't gonna play Sun City," the record indicts performers who have accepted bookings at the resort, located in a rural, poverty-ridden area of Africa. Bophuthatswana is one of the nominally independent "tribal homelands" created by the government of South Africa, and despite a United Nations-sanctioned cultural boycott of the country, Sun City continues to attract major performers by offering extremely high commissions. Frank Sinatra, for instance, was reported to have been paid $1.79 million for a nine-day engagement at Sun City's Superbowl in July 1981.

All artist royalties from the project will go to the Africa Fund, a nonprofit, United Nations-sanctioned organization that will use the money for antiapartheid programs in the United States and South Africa. But fundraising is not the key issue with "Sun City"; Van Zandt has said that the prime goals of the record are to raise American consciousness about the situation in South Africa and to encourage entertainers to boycott Sun City. Every record will contain an insert explaining the cultural boycott.

While Band Aid's "Do They Know It's Christmas (Feed the World)" and USA for Africa's "We Are the World" avoided political commentary in their mainstream pleas for listeners to open their hearts and, more importantly, their checkbooks to famine victims in Africa, there is no mistaking "Sun City's" impassioned political message:

Relocation to phony homelands, separation of families I can't understand

23 million can't vote because they're black

We're stabbing our brothers and sisters in the back . . .

"Sun City" also is critical of the Reagan administration's policies in South Africa:

Our government tells us we're doing all we can

Constructive engagement is Ronald Reagan's plan

Meanwhile people are dying and giving up hope

This quiet diplomacy ain't nothing but a joke.

"Sun City" is an extension of a slowly evolving political consciousness within the music community, spurred on by the African hunger relief projects and focused through the Farm Aid benefit and various AIDS-related singles now being released.

It is not the first pop record to attack apartheid, however. Gil Scott-Heron's "Johannesburg," released almost 10 years ago, was a minor hit, and the Specials/AKA's "Free Nelson Mandela" was a huge hit in England last year. Randy Newman's "Christmas in Capetown," many tunes by the integrated African group Juluka and, more recently, Stevie Wonder's "It's Wrong" also have criticized apartheid.

The "Sun City" project resulted from two trips Van Zandt made to South Africa during the past 12 months. On his return, he started to put together a small session of friends to record several new songs inspired by his experiences there, but word soon got out to the music community. Eventually, Artists United Against Apartheid ended up participating in recording sessions in New York, Boston, Los Angeles and London.

"Sun City" follows a now familiar pattern of different lines for different singers resolving in an anthemic chorus. The nicest symmetry occurs on the line "We're stabbing our brothers and sisters in the back," sung early by Springsteen and later by Bono, two rock artists for whom social commitment has become a central motif.

The participants represent the gamut of current pop styles, from rap (Afrika Bambaattaa, Kurtis Blow, Run-DMC, Melle Mel), rock (Pat Benatar, Lou Reed, Pete Townshend), jazz (Miles Davis, Stanley Jordan, Herbie Hancock), reggae (Big Youth, Jimmy Cliff), R&B and funk (George Clinton, Nona Hendryx, Bobby Womack, David Ruffin and Eddie Kendricks) to Latin and African music (Sunny Okussons, Ray Barretto, Reuben Blades, the Soweto-based Malopoets).

The "Sun City" single is much harder and aggressively rhythmic than its all-star predecessors, which may limit its radio exposure. The 12-inch remix version, directed at the dance floor, is even harsher, emphasizing the rap side of the sessions. As various artists offered their own musical variations on Van Zandt's original theme, the project evolved into a six-track album.

The tracks include the original all-star arrangement, aimed at mainstream radio, as well as the dance club remix. There's also a very hard-hitting rap number, "Let Me See Your ID," featuring Ray Barretto, Peter Wolf, Duke Bottee, Big Youth, Grandmaster Melle Mel, Peter Garrett of Midnight Oil, the Malopoets and Washington's own Gil Scott-Heron, who begins his rap, "I was watching TV the other night, when who should appear but Walter Cronkite with the blues . . ."

A jazz instrumental arrangement, "The Struggle Continues," reunites Miles Davis with old Quintet-mates Herbie Hancock, Tony Williams and Ron Carter, as well as guitarist Stanley Jordan and Sunny Okussons. "The Revolutionary Situation" is a spoken-word cut with excerpts from speeches by imprisoned South African leader Nelson Mandela and Nobel Peace Prize winner Bishop Desmond Tutu, while "No More Apartheid" is an improvisational piece by Peter Gabriel and the Indian violinist Shankar.

A video of the single, directed by Jonathan Demme and edited by Godley & Creme, is also in the works. There was a big shoot last week at New York's Washington Square with Little Steven, Springsteen, Bono, Run-DMC and others. Over the weekend, Bob Dylan and Jackson Browne were filmed in Los Angeles, while Ringo Starr and his son Zak Starkey were filmed in London.