A 71-year-old Murchison man has been arrested in connection with a series of forest fires south of Nelson.
Police allege that he lit the fires between early February and this month.
His arrest came after a 15-week joint investigation by Tasman police, Nelson Forests Ltd and the Rural Fire Network.
Detective Senior Sergeant Wayne McCoy says that when police officers and armed offenders squad members searched the man's house early on Thursday morning they found cannabis and a large amount of ammunition and have charged him with firearms and drugs offences as well as arson.
The man will appear in Nelson District Court on Friday.