Drugs, alcohol and knives were among prohibited items found by Corrections Department staff during a routine search of visitors to the Otago Corrections Facility last week.
The find was a reminder that visitors would be caught if they tried to sneak in contraband, prison manager Jack Harrison said.
Several people received warnings after staff searched seven cars and their occupants at the prison on Thursday, leading to the discovery of a number of prohibited items, including alcohol, knives and cameras.
One woman was found with a cannabis pipe, unauthorised prescription pills, and a small resealable plastic bag containing the residue of a white powder.
The items were confiscated and police notified, Mr Harrison said.
The woman was issued an exclusion notice and asked to leave the prison.
"Hopefully she now understands that bringing this sort of stuff to a prison just isn't acceptable," Mr Harrison said.
"Ignorance is not an excuse. There are signs at the Prison gates clearly spelling out what is banned, so the message is clear - if you want to visit the prison make sure you don't have anything dodgy in your car or on your person."
