Thousands walk through Auckland's long-awaited Waterview Tunnel
Tens of thousands of people are experiencing Auckland's 2.4km, $1.4 billion Waterview Tunnel on Sunday.
An opening ceremony and ribbon cutting - attended by Prime Minister Bill English - started at 10.30am, with thousands of pedestrians and cyclists - who booked the event out within hours - now making their way through the tunnel.
"This a very exciting day for Auckland," English said.
"It has been 60 years in the making and there are many other major projects in the pipeline.
"I know the public will really appreciate it, and I hope they'll have a real sense of ownership with this next step."
The massive roading project was earmarked to open at Easter, but holdups due to a fault with the tunnel's jet fan and water extraction pump system have meant vehicles won't be allowed in until early July.
Transport Minister Simon Bridges touted the tunnel as the biggest change to Auckland traffic flows since the opening of the Harbour Bridge.
He too acknowledged workers at the opening ceremony.
"We really need to thank the workers, some 11,000 people have worked on this tunnel - 1800 a day at its peak," Bridges said.
After the ceremony, thousands began to pile through the entrance of the tunnel as Auckland mayor Phil Goff greeted the excited crowd at the entrance.
One spectator said it was a fabulous experience and a great piece of engineering. When asked why he wanted to be one of the first to walk through he said: "I just had to, it's a part of Auckland history."
The tunnel and associated ring road will connect Auckland's northwestern and southwestern motorways.
They are the final links in the 48km Western Ring Route, which is expected to reduce inner-city traffic by offering an alternative to the Harbour Bridge that skirts the Waitemata Harbour.
Construction kicked off in 2012 and excavation traditions dating back to early mining days had been carried out in the process - the naming of major machinery, for one.
A state-of-the-art boring machine dubbed Alice removed 800,000 cubic metres of earth, enough to fill 320 Olympic-sized swimming pools, as part of the tunnel's construction.
Alice was named by local school children after Alice in Wonderland, due to their shared propensity for subterranean exploration and was 87m in length.
Dennis the gantry, capable of hoisting concrete beams weighing 65 tonnes, was named after a project worker who died of cancer before the tunnel's completion.
Inside the tunnel there is enough wiring to stretch from Auckland to Waiouru, and the scale of its paint job could cover Auckland Airport three times over.
The tunnels are the longest road tunnels in New Zealand – the Lyttleton road tunnel at 1.97km previously held the record.
Construction included laying almost five km of drainage pipes, installing 104 flame traps, 4000 lights, 62 ventilation fans, 400 km or 270 tonnes of cabling and wiring, and five deluge storage tanks each containing 250,000 litres of water for fire control.
The New Zealand Transport Agency said while the tunnels are not designed to remove congestion altogether, the Western Ring Route as a whole will provide a better balance of traffic flows across the entire network and will help remove cars from local roads.
It will also provide more transport options including bus lanes and walking and cycling connections.