UB40 has not been scheduled to perform in South Africa, the band said in a statement on Monday.
"We would like to make it known to all UB40 fans in South Africa that the current shows being advertised at several venues in South Africa as UB40 shows are not genuine," said the five remaining founding members of UB40 -- Robin Campbell, Brian Travers, James Brown, Earl Falconer and Norman Hassan.
The band said three former members of UB40 had made an announcement about several live performances in the country.
"Three former members of UB40, Ali Campbell, Astro and Michael Virtue, are fraudulently masquerading as UB40," the band said.
UB40 said Campbell left the band six years ago citing issues with the band's management and had since pursued a solo career.
"While their actions are highly immoral, they are also illegal, and we are currently pursuing the matter through the law courts," UB40 said.
The band said it was in talks with Big Concerts promoter Attie Van Wyk to perform in the country.