Manufacturing is the largest contributor to Whangārei's GDP. Manufacturing businesses include processing industries such as oil refining, dairy factories, wood-processing mills and cement manufacturing facilities. These businesses are critical to Whangārei's primary industries, turning primary products into manufactured goods.

Whangārei is home to the only foundry in Northland. Operated by Circa Marine, it provides marine, industrial and general engineering sectors with quality aluminium and steel for a strong manufacturing / trades sector.

Refining NZ, located at Marsden Point, is changing. Now Channel Infrastructure will utilise Refining NZ's assets to store and transport fuels. 

Other notable manufacturers in Whangārei include;

Culham Engineering, one of New Zealand's largest fabrication facilities

SPIIND provides onsite mechanical and electrical maintenance services to industries throughout New Zealand including oil, dairy, timber, cement, water and engineering

McRaes Global Engineering Ltd is a leading expert in hydraulics, engineering and controls

Hansen Products design, manufacture and distribute pipe fittings and valves around the world

Golden Bay Cement is New Zealand's largest and most enduring cement manufacturer and supplier