RCMP say officers got a search warrant after learning stolen items were being kept in a home.
Sgt. Sheryl Armstrong alleges police found a .45-calibre, semi-automatic machine gun, a loaded sawed-off shotgun, tools, stereo equipment and stolen IDs among other things.
Armstrong says on Friday, one of the suspects was arrested after officers allegedly found four firearms and hundreds of rounds of ammunition in his van.
Police say both men in custody are 37 years old and the woman is 27.
Armstrong says all of them are from Nanaimo and officers continue to investigate.