Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Probably in the family: Sapromyzidae

This little brown fly is probably in the family Sapromyzidae but it is hard to tell for sure - these little flies need an examination of wing veins plus counting various bristles on the head and thorax for accurate ID to family level and beyond.

Photographed October New Plymouth
Fly Sapromyzidae.JPG

Photographed New Plymouth March
Brown fly probably in the family Sapromyzidae-001.JPG

Brown fly probably in the family Sapromyzidae-002.JPG

Brown fly probably in the family Sapromyzidae-003.JPG 

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0