The Makarewa River is the largest tributary of the à Âreti River, and is in Southland, New Zealand. It flows for from its source in the Hokonui Hills, joining the à Âreti just north of Invercargill. The river lies within the Makarewa Groundwater Management Zone which covers an area of approximately 66,000 ha. Makarewa River is a location for the fishing of brown trout.