More than 100kg of dagga was seized from a shack in Dunoon, Cape Town, on election day, police said on Thursday.
Table View police spokesperson Captain Adriana Chandler said officers, acting on a tip-off about a "dagga enterprise", went to a shack in Site 5 on Wednesday.
When they arrived two men were on their way out of the shack. Police asked if they lived there, and asked for permission to search the place.
The men gave the police access to the shack and they found a woman sitting inside.
"During their search of the premises the officers found two large 80kg bags. One was filled with cannabis, and the other bag was half-filled," said Chandler.
The three were arrested for allegedly dealing in an illegal substance and were taken into custody at the Table View police station.
Two are in their 20s and one is 40.
Chandler said 120kg of dagga was handed in as evidence.
The three are expected to appear in the Cape Town Magistrate's Court on Friday, May 10.
The Constitutional Court ruled last year that it was unconstitutional to criminalise personal use of dagga.
However, Parliament still has to thrash out how sales, transport and use of the plant will be regulated.
Milnerton cluster commander Major General Aneeqah Jordaan welcomed the arrest of the three and thanked residents for tipping off police.