Detective Sergeant Adam Forehan, of the Colac police crime investigation unit, said a search warrant was executed at an address on Tuesday.

"Located was a small cannabis grow house containing nine mature cannabis plants," he said.

The street value of a mature cannabis plant is about $2000.

"Two long arms and a large quantity of ammunition were also uncovered. Inquiries into those firearms are continuing," Detective Sergeant Forehan said.

"A 46-year-old Colac man was arrested and charged with possessing and cultivating cannabis. He will appear in the Colac Magistrates Court on January 28 after being released on bail."

Detective Sergeant Forehan said said police still wanted to speak with a 17-year-old male who they believe can assist them with inquiries into the firearms.

"It was a very pleasing result to have two illicit firearms off the streets and out of the community," he said.

"The origins of those firearms are yet to be established and they'll be subjected to forensic examinations," he said.

Anyone with information about drugs or firearms is requested to contact Crime Stoppers on 1800 333 000.

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