Ninety undocumented Ethiopian nationals, who were allegedly being kept against their will and under inhumane conditions, have been rescued in Sunnydale Ridge, Johannesburg by the South African Police Service (SAPS) Special Task Force (STF) unit.

"A multidisciplinary team, led by the STF, were tracing a victim of kidnapping for ransom when they they also made the discovery of the undocumented nationals who were found locked up, confined and packed into rooms.

"Investigations are underway as to how these nationals were trafficked into SA," said the police in a statement on Sunday, adding that the Ethiopian nationals were all taken to hospital for medical care.

Among the Ethiopian nationals was the kidnapped victim who was also rescued.

The victim had been kidnapped in Benoni on Tuesday afternoon and his kidnappers immediately started demanding hundreds of thousands of ransom money from his family.

Two alleged human traffickers and kidnappers who were found on the property have been arrested and are likely to face charges of kidnapping and human trafficking.

They are expected to appear before the Palm Ridge Magistrate's Court soon.

The case has been handed over to the Directorate for Priority Crime Investigations (HAWKS) for further investigations.

The police said the operation would not have been successful without the work of the crime intelligence unit, organised crime detectives unit, Sandringham and Daveyton SAPS as well as private security.