A 28-year-old man has been charged with offences including possession of firearms, ammunition and explosives.
He is also charged with four drugs offences.
A PSNI spokeswoman said the suspect had been detained in Londonderry on Thursday by officers from the serious crime branch.
A number of items were seized when police searched a house in Hawkin Street in the city.
The man is due to appear before a special sitting of Derry Magistrates Court.