1. (pronoun) I, me - unlike other pronouns and personals, does not take a when following ki, i, kei and hei. Does not take a when used as the subject of the sentence. Never occurs after he, te and ngā and is not used after the prepositions a, o, mā, mō, nā, nō or with tā and tō.

(Te Kākano Textbook (Ed. 2): 13, 15;)