"The vehicle was allegedly travelling from Lesotho en route to Upington when police signalled them to pull over," said police spokesperson Capt Sergio Kock.
The vehicle's occupants fled into the veld but were chased down on foot and arrested.
"The vehicle was searched and police found 200kg of dagga with an estimated street value of about R1.5m stashed inside. Police also confiscated the vehicle as it was utilised in the commission of a crime," said Kock.
Acting Upington station commander Col Eve April commended the officers for their dedication and vigilance.
"We will continue to turn the tide against crime and squeeze the space for criminals to operate in Upington and surrounding areas," said April.