The Saturday Star reported that the case would be heard by the High Court in Johannesburg on Tuesday.
The National Union of Metalworkers of South Africa (Numsa) wants the court to force City Power to reveal records and documents that led to the awarding of a tender to manufacture solar water heater geysers to Tasol Solar Energy Solutions.
Numsa told the newspaper the company was itself importing the units from China when they could have been manufactured locally to support employment in the metal industry.
Numsa treasurer Mphumzi Maqungo accused City Power of failing to prioritise local companies when awarding the contract.
He said when the union asked City Power to disclose all the information regarding the awarding of the tender, it was given blank documents.
"We are not casting aspersions on City Power but we want transparency. They have failed to share this information with us for the past 12 months," he was quoted as saying.
Accusations not true
City Power told the newspaper it was ready to defend itself in court, and its legal head Andrew Lishivha said accusations by the union were not true.
"With regard to the information on the scores obtained by companies which bid for the tender, we are unable to accede to Numsa's request as it consists of confidential information that related to third parties," he said. – Sapa