The twin tunnels at the Waterview Connection are on schedule to open to motorists early next year.
The tunnels are part of New Zealand’s largest ever roading project – connecting Auckland’s north, south and West.
It’s known as the "missing link" of a motorway ring that will circle the city.
At 2.4 kilometres each, the tunnels will be the longest in New Zealand.
While the structure is physically complete – crews are now working on the fit-out.
"This is the fun stuff. So the structure is complete, it’s all about fitting it out to make the tunnel work. For the mechanical electrical fit out this is the busiest period. We’ve probably got about 250 guys on site," says David Taylor, the project’s mechanical and electrical construction manager.
The fit-out includes 140,000sqm of paint for the roof and walls, 4000 lights, 400 kilometres of cabling and wiring as well as 62 ventilation fans.
The tunnels are also equipped with five storage tanks to release huge amounts of water should a fire break out inside.
Each tunnel will have three lanes and at a maximum each lane will be able to handle 2400 vehicles per hour.
New Zealand Transport Agency Highway Manager Brett Gliddon believes the whole intersection will make a big difference to Auckland traffic.
"It’s not going to fix all the problems but to finally complete that ring route is a big step for Auckland and that provides so much resilience to our network which is what is missing at the moment."
The project is costing $1.4 billion.