Onerahi Causeway
The Onerahi Causeway is a road in the Northland region of New Zealand. It connects the suburb of Onerahi with the city of Whangārei and is about 5 kilometres long. The causeway crosses the marshes and seabed of the upper Whangārei Harbour and carries around 20,000 vehicles a day along Riverside Drive, making it one of the region’s busiest roads.
Construction happened from 1950 to 1953, built by Whangārei County to improve links between Whangārei and Onerahi, Parua Bay, Whangārei Heads, and Whangārei Airport. Previously the route ran along the harbour’s northern shore with many small one-lane bridges over streams like the Awaroa River and Mackesy Stream (the old piles are still there). The project drained some harbour areas and raised the road to avoid spring-tide flooding, creating a straight, flat road with three bridges. It also brought sewerage and water services to Onerahi and led to the closure of the Onerahi waste treatment works.
The new road greatly improved travel to Onerahi, which had been neglected after the Onerahi Branch Railway closed in 1933. In 2016, a 6-kilometre cycleway was added along the causeway, widening part of the reclamation. The cycleway links the Waimahanga Walkway and Hatea Loop to help people walk and cycle from Onerahi to central Whangārei.
Today, the causeway is a major route, connecting Onerahi and Whangārei Heads to Whangārei city. In 2010, the council said the road would be four-laned by 2016 to ease congestion, but that plan has not been funded and was dropped from current plans as of 2025. Any future expansion is expected to be tied to the planned Onerahi Bypass when that project is built.
This page was last edited on 2 February 2026, at 13:29 (CET).