Police discovered drugs and firearms following search warrants in and around Gore and Riversdale.
Over the past two days Eastern Southland Police targeted drug suppliers.
Operation Nightforce was assisted by extra staff from the District and a drug detection dog from Te Waipounamu.
Senior Sergeant Gary Iddenten from Southern Police says the operation targeted several addresses and that two people were arrested without incident.
"We found cannabis cultivation, a firearm and other Class A and B drugs."
A 20-year-old man is in custody and will appear in Invercargill District Court on 25 March to face over 20 drug possession and supply charges.
A 39-year-old woman was also arrested for breach of bail for previous active charges.
Senior Sergeant Iddenten says investigations are continuing and that further prosecutions are expected.
"We will continue to target those who supply drugs no matter where you live.
"Substances like these have the potential to cause extreme harm and damage in our communities.
