The Otamatea River is a river of the Northland Region. A short, wide river, It flows southwest and could be considered an arm of the northern Kaipara Harbour

Kaipara Harbour

Kaipara Harbour is a large enclosed harbour estuary complex on the north western side of the North Island of New Zealand. The northern part of the harbour is administered by the Kaipara District and the southern part is administered by the Rodney District...

. The Otamatea is formed by the confluence of the Wairau and Kaiwaka

Kaiwaka River

The Kaiwaka River is a river of New Zealand's Northland Region. For much of its length, it is a broad arm of the Otamatea River, as much an inlet of the Kaipara Harbour as a true river.-References:...

 rivers and the North Auckland Line crosses at this point. Almost 300 metres (328.1 yd) wide at its origin, the river widens to 1.8 kilometres (1.1 mi) by its mouth opposite Tinopai

Tinopai

Tinopai is a settlement on the Komiti Bay, part of the Hukatere Peninsula in the northern Kaipara Harbour in Northland, New Zealand. The Otamatea River flows from the north east past Tinopai and into the harbour. Matakohe is to the north....

. Several other broad tidal creeks flow into the Otamatea, including Raepare Creek, Awaroa Creek, Takahoa Creek and the Whakaki River

Whakaki River

The Whakaki River is located in the Northland Region of New Zealand's North Island. Despite its name, it is better described as a silty arm of the Kaipara Harbour. It flows northwest to reach the Arapaoa River.-References:...

 on the left bank and the Arapaoa River

Arapaoa River

The Arapaoa River is a northeastern arm of the Kaipara Harbour in Northland, New Zealand. Officially designated as a river, it is some 17 kilometres in length and an average of three kilometres in width.-References:* - Search for Place Names...

on the right.