N.H. Rev. Stat. Ann. § 438:15

With respect to the enforcement of this chapter and any other law dealing with weights and measures that he or she is or may be empowered to enforce, the commissioner, or the commissioner's inspectors at his or her direction, is hereby vested with special police powers, and is authorized to arrest, without formal warrant, any violator of said laws, and to seize for use as evidence, without formal warrant, incorrect or unsealed weights and measures or amounts or packages of commodity found to be used, retained, offered, or exposed for sale or sold in violation of law.