Seven suspects - including local government officials and a former African Nation Congress (ANC) spokesperson - have been charged with fraud in a South African court.
The defendants appeared in court following an investigation into a 27 million rand (£1.2m; $1.6m) government tender.
The investigation found that five years ago the provincial government in Gauteng signed a contract with a company named Enviro-Mobi for waste management services.
Enviro-Mobi did not disclose that it had links to ex-ANC spokesperson Pule Mabe, who was an MP at the time, a police statement said.
The suspects were not asked to enter pleas but Mabe and his wife denied the allegations.
The court hearing took place on Wednesday after the seven suspects had handed themselves into South Africa's elite police unit, the Hawks.
Alongside Mabe and his wife, the defendants included two executives from Guateng's provincial government.
All seven accused were awarded bail at the hearing, which took place in Ekurhuleni, a municipality just east of the city of Johannesburg.
Outside the courthouse, Mabe told local media he was stepping down from the ANC's executive committee, but "not because he is guilty".
The contract in question stipulated that Enviro-Mobi should receive upfront payments and that money should only be handed to the company after a portion of its work was completed, police spokesperson Thandi Mbambo said.
However, the Hawks' investigation found that Gauteng's Department of Agriculture paid Enviro-Mobi 25 million rand for 200 vehicles, even though the goods were "still in the possession of the service provider".
It is not the first time Mabe, who served as the ANC's spokesperson from 2018 to 2023, has been accused of corruption.
Along with two others, he was arrested in 2013 over allegations he had defrauded the South African Social Security Agency (Sassa). The trio were later cleared of all charges.
And in 2017 Mabe was fined after a parliamentary committee found that he had benefited from a contract with the state-owned rail company.