Me. Rev. Stat. tit. 18-C, § 5-212

In any proceeding under this Part, including for issuing, modifying or terminating an order of guardianship for a minor, the court may appoint a guardian ad litem for the minor. The appointment may be made at any time, but the court shall make every effort to make the appointment as soon as possible after the commencement of the proceeding. The court shall follow the requirements of section 1‑111 and other applicable law or court rules in making the appointment.