More arrests were likely, the officer in charge of the Otago Rural CIB, Detective Senior Sergeant Colin Blackie, said yesterday.
Police had seized class B and class C controlled drugs, including methamphetamine and BZP, drug utensils, 10 firearms, explosives and ammunition during searches of 11 properties in Central Otago and Invercargill.
The New Zealand Defence Force bomb disposal squad from Christchurch was called to Alexandra last night to deal with a small amount of explosives located in a house during searches as part of the operation, dubbed Operation Walton.
The explosives were two railway detonators, a bomb squad member, who declined to be named, said.
The man said the detonators were usually used as a signal to warn train drivers of track works ahead. They exploded as the wheels of a train hit them.
Five men and two women face a variety of drug-related charges, including selling, supplying and offering to supply class C controlled drugs, possession of, and possession for, supply of class B and C controlled drugs, possession of drug instruments, unlawful possession of explosives and charges of arson.
Det Snr Sgt Blackie said those arrested would appear in the Alexandra District Court over the coming weeks.
Operation Walton resulted from a spate of arsons, burglaries of properties and thefts of firearms, and from targeting people involved in drug dealing in Central Otago.
The arsons were around Alexandra, near the pine reserve on the outskirts of the town, while the firearms were taken during burglaries in Lauder and Alexandra.
"The series of seven arsons were real reason for concern, plus the burglaries and the firearms, which just ramped up that concern," he said.
The drugs seized had yet to be weighed and bagged, so he was unsure of the quantity involved.
Twenty police officers from Central Otago, Queenstown, Wanaka and Invercargill were involved in the operation.
He expressed gratitude to volunteer firefighters, who had assisted the operation, and also praised members of the public who provided information.
"The fire staff have been brilliant throughout this inquiry and we appreciate their help."
