Justice Minister Tareck El Aissami says the 28-year-old was detained Thursday in the southwestern city of El Vigia after a weeklong investigation. The man's identity has not been released.
El Aissami says the man has traveled frequently to Colombia and police found messages on his computers alluding to a plot to kill Chavez involving Colombia's outlawed right-wing paramilitary groups.
Tensions are strained between Colombia's conservative government and Chavez's socialist administration.
Venezuelan authorities have claimed numerous purported plots against Chavez in recent years, but none have led to arrests.