Heroin worth R50m destined for Gauteng has been seized in what is believed to be one of the biggest drug busts.

A member of the WhiteRiver K9 Unit pulled over a suspicious looking Toyota Prado at the Nkomazi Toll Gate on the N4 in Mpumalanga on Sunday.

The officer and his dog searched the vehicle. The dog reacted positively to one of the car’s two fuel tanks.

Police spokesperson Sergeant Gerald Sedibe said upon searching, they found the heroin stashed inside the fuel tank.

“Drugs estimated at R50 million were found stashed inside a petrol tank. The car was coming from Mozambique heading to Gauteng,” he said.

After removing the tank and investigating further, police discovered pure Afghani Heroin.

The drugs were packed in small bags neatly stashed inside the tank.

The driver of the vehicle was arrested.