| Omanaia River | |
| Mouth Location: | Hokianga Harbour |
| Subdivision Type1: | Country |
| Subdivision Name1: | New Zealand |
| Length: | 14km (09miles) |
The Omanaia River is a river of the Northland Region of New Zealand's North Island. It flows northwest from the Waima Forest, first as a stream and then as a silty arm of the Hokianga Harbour. The township of Rawene stands at the point where the river meets the main waters of the harbour.