Heroin, morphine and ecstasy pills are just some of the illegal substances intercepted by the New Zealand Customs Service in the South last year.
Figures released to the Otago Daily Times under the Official Information Act detail drug interceptions nationally and in Otago and Southland for the year ending November 30, 2012.
Southern interceptions included an incident where 1.2g of heroin was detected at Queenstown Airport last year.
Customs officers at Dunedin International Airport also seized 142g of the stimulant drug ephedrine, which has a similar chemical structure and similar biological effects to amphetamines.
There was also one incident where 85 cannabis seeds were recovered from a passenger at Dunedin.
Of the 18 interceptions, a dozen were for controlled medicines and prescription medicines.
When a person arrives in New Zealand they were required to declare the possessions of any prescription medicine, have a copy of their doctor's prescription and carry the medicine in its original container.
If the criteria are not met, Customs can detain the medicines and record them as a prohibited drug interception.
A Customs spokeswoman said goods found at the border that were categorised as pseudoephedrine products - those which could be used to produce methamphetamine - accounted for the largest quantity of interceptions, with 426kg and one litre recovered by officials.
Also intercepted at the country's border were 25,000 tablets of ephedrine, 200ml of opium, 5.6kg of methamphetamine, and 75ml of the aphrodisiac Spanish Fly.