N.H. Rev. Stat. § 491:14
Suits in equity, petitions for divorce, nullity of marriage, alimony, custody of children, allowance to wife from husband's property, new trials, redemption and foreclosure of mortgages, writs of mandamus and quo warranto, and other similar proceedings may be heard upon oral testimony or depositions, or both; or when both parties consent, or service having been made and a notice of the time and place of the hearing having been given, when both parties appear, such suits may be heard by any justice of the court at any time, but nothing contained in this section shall be construed as limiting the power of the court to have issues of fact framed and tried by a jury, according to the rules in equity, or the course of such proceedings at common law.
RSA 491:14
1870, 2:1. GL 208:3. PS 204:9. PL 316 :11. RL 370:12. RSA 491:14. 1992, 284:12, eff. Jan. 1, 1993.