N.H. Rev. Stat. § 275:39
An employer who violates the provisions of RSA 275:37 shall be liable to the employee or employees affected in the amount of their unpaid wages, and in an additional equal amount of liquidated damages. Action to recover such liability may be maintained in any court of competent jurisdiction by any one or more employees for and in behalf of himself or themselves and other employees similarly situated. At the request of any employee paid less than the wage to which she is entitled under this subdivision, the labor commissioner may take an assignment of such wage claim in trust for the assigning employee and may bring any legal action necessary to collect such claim, and the liquidated damages above provided for. The commissioner shall not be required to pay the entry fee, or other costs, in connection with such action. The commissioner shall have power to join various claimants against the employer in one cause of action.
RSA 275:39
1947, 193:4, eff. July 1, 1947.