The Police Special Task Force personnel have recovered a kilogram of heroin and 50 grams of narcotics known as ICE from Yatadolawatta, Matugama.
The stock of narcotics has been seized from a house which is under construction.
Police Media Spokesman Senior Superintendent of Police Nihal Talduwa said a firearm was also recovered from the residence.
Investigations have commenced to identify and apprehend the owner of the firearm and the stock of narcotics. The Police Narcotics Bureau is conducting further investigation.