The word hiahia means "to want". This can be added to another word, like moe (sleep), kia (food) and wai (water):
Kei te hiamoe ahau.
I am tired (literally: I am sleep wanting).Kei te hiakai ahau.
I am hungry (literally: I am food wanting).Kei te hiawai ahau.
I am thirsty (literally: I am water wanting).
In the same way, the word mate (sick, dead) can be added to a word:
Kei te matemoe ahau.
I am exhausted (literally: I am sleep sick).Kei te matekai ahau.
I am starving (literally: I am food sick).Kei te matewai ahau.
I am parched (literally: I am water sick).