Johannesburg - Fifty-six shipping containers carrying alleged illegal clothing imports were detained at the China Shopping Centre, south of Johannesburg, the SA Revenue Service (Sars) said on Monday.
Spokesperson Anton Fisher said 12 people were arrested for alleged immigration offences in the operation last Thursday.
Officials seized files from clearing agents, who may have been involved in the irregular importation of clothing and textiles.
They also removed equipment suspected of being used to make counterfeit CDs and DVDs as well as false ID books and passports.
The equipment as well as the goods in the containers was valued at about R10m.
"One of the biggest threats remains the under-invoicing of import clothing and textile consignments, resulting in low revenue flows into the fiscus," Fisher said.
He said this was a burden for an industry rocked by significant job losses over the past few years.