AN INVESTIGATION into stolen firearms and farming equipment has uncovered a "sophisticated” hydroponic marijuana crop growing in a caravan at Tabulam.

A 43 year-old Tabulam man was arrested after police executed a search warrant on a Tabulam farm at 3pm on Monday and found more than 250 plants ranging in maturity and size, from 10cm to one metre, as well as ammunition. Hydroponic growing equipment was also seized.

The plants had an estimated street value of $350,000.

The Tabulam man was due to face Lismore Local Court yesterday facing charges of cultivating more than a commercial quantity of a prohibited drug, possession a prohibited drugs, possessing ammunition without a licence, and taking part in enhanced indoor cultivation of a prohibited drug (commercial quantity).

He also had an outstanding warrant executed.

Detective Chief Inspector Cameron Lindsay said that it was a "commercial amount” of drugs seized and was concerned about the potency of the hydroponic drug, saying the chemicals used in the growing process made them more potent than bush grown plants.

Detective Chief Inspector Lindsay said the search warrant was initially executed as part of an ongoing investigation into firearm and farm machinery theft from rural properties, but wasn't surprised drugs were found.

"This probably highlights a connection between the commercial growing of cannabis and other illegal activities,” he said. " It's not a surprise when we are looking for stolen items that we've found a set-up like this.”

An ongoing investigation continues.