The SA Revenue Service (SARS) and the SA Police Service (SAPS) have seized more than 12 700 cases of duty-free liquor worth R15 million from a warehouse in Mpumalanga, the tax agency said in a statement on Tuesday.
This followed a year-long investigation conducted with the help of the liquor industry, SARS said.
Officials also found equipment used to tamper with the original products to facilitate smuggling.
The bottles and boxes used to transport the alcohol have labels indicating that the product is duty free and destined for export. But smugglers removed these labels from the bottles and replaced them, SARS said, or sometimes replaced the caps of the bottles or removed lot codes from the boxes.
SARS Commissioner Edward Kieswetter said the smugglers of the illicit liquor were harming the local industry at a time when Covid-19 restrictions were already a significant impediment to the sector.
The alcohol industry in SA has taken a battering under lockdown, having faced partial restrictions as well as a series of total sales bans.
In May, a new report commissioned by the sector found that local illicit alcohol trade has reached over R20 billion, and that one in every 4.54 litres of alcohol sold is illegal. This includes counterfeit products, unbranded alcohol, home-brewed liquor and smuggled alcohol.
The illicit market now makes up some 12% of the R177-billion industry, the report found.
On Tuesday, Kieswetter reiterated that "all those involved in this smuggling network will be brought to book".
"We are committed to making it hard and costly for any taxpayer or trader who does not comply with the tax or customs laws of the country," he said.