N.H. Rev. Stat. Ann. § 21-J:20

The commissioner may cause an audit to be made of the accounts of any city, town, school district, or village district or precinct, as often as once in 2 years, or whenever conditions appear to him to warrant such audit. The accounts of all county officers shall be audited annually by a certified public accountant, and a complete report of such audit shall be made available to the public.