Ferromagnetism (FM) in GaMnN was found to be related to the position of the Fermi level relative to the Mn deep-level band. The location of the Fermi level can be altered by doping GaMnN with Si (n-type) and Mg (p-type) dopants, resulting in a ferromagnetic to paramagnetic transformation. We have found that this manipulation of the Fermi level also can affect the optical properties of GaMnN, GaMnN: Mg and GaMnN: Si. The major optical absorption bands were found either to be enhanced or diminished depending on the level and nature of the doping elements. Therefore, a correlation between optical properties and saturation magnetization of GaMnN can be established.