The woman, 33, who is a foreign national, had been travelling in a truck on the N1 when the Central Karoo K-9 unit pulled the vehicle over in the early hours of Tuesday morning, said Captain Malcolm Pojie.
They seized cocaine with an estimated street value of R830 800 and arrested her on a charge of dealing in drugs.
Provincial detectives from the narcotics unit would investigate further.
The woman will appear in the Beaufort West Magistrate’s Court on Wednesday.