Three luxury cars travelling in KwaZulu-Natal for the ANC centenary celebrations had the same number plates, the Witness newspaper reported on Friday.
Pictures of an Audi and a Mercedes Benz with members of the ANC dressed in party regalia either standing in the cars waving flags or standing next to them were posted on Facebook.
The Witness newspaper said it was not clear when or where the pictures were taken. The number plates were both ANC 100-ZN.
According to South Africa's Road Traffic Act it is illegal to have the same number plates on different cars.
"We are looking into this matter and we do not know these cars. We would like to get hold of the full details of the vehicles," ANC provincial secretary-general Sihle Zikalala was quoted as saying by the newspaper.