After 30 years trying to open up the huge tunnel complex beneath central Auckland's Albert Park, Bill Reid may finally be getting near his pot of gold.

Photo: 123RF

Mr Reid and his two subterranean-loving associates have made a bid to a private finance consortium seeking tens of millions of dollars to fund a project they believe would be one of Auckland's greatest assets.

If all goes to plan, the tunnels would include a cycleway from the city to Parnell, a glow worm cave, blackwater rafting, a troll's lair, shops, cafes and underground bars.

Mr Reid and his two business partners want to excavate a labyrinth of tunnels - the main one being a 660m stretch running from Victoria St to Beach Rd.

It would become a cycle and walkway providing quick access from the CBD to Parnell, with dozens of smaller side tunnels offering opportunities for retail, hospitality and quirky tourist attractions.

The tunnels would also have two elevators providing access - one from Princes St near the university, the other from Symonds St.

Auckland Council has, in principle, unanimously backed the plan and now what's needed is a concrete business case - as well as money.

On that front, Mr Reid made a pitch to a wealthy funding consortium on last Tuesday and he hopes they see the same business opportunities that he does in the project.

"I was in discussions with a major banking source for the full funding of the whole project - not just the resource consent," he said.

When Japan entered the Second World War in 1941, more than 100 men began cutting through the sandstone and volcanic rock beneath central Auckland.

With just picks, shovels and hand-carts, in just three months they dug a 3.5 kilometre network of tunnels capable of sheltering over 20,000 from the bombs that were feared would fall over the city.

The air raids never came and in 1946 the tunnels were sealed off by 8.8 million clay bricks.

The incredible feat of engineering - and hard-graft - was lost, seemingly forever.

But after a 30-year quest to see the tunnels opened to the people of Auckland, Mr Reid feels he may be close to realising his dream.

"All I am offering is something that was hidden, sealed on the 28th of February 1946, never to be seen again, and it's been a very, very expensive exercise for me to get to where we are now."

Nicolas Reid - no relation - is one of Bill Reid's partners in their Subterranean City company,

He said the project would cost between $19 million - enough to get the tunnels open to the public to a basic standard - and $100 million which would get things like blackwater rafting into the centre of Auckland.

"The way we have developed the business model... is a privately-funded investment, one that delivers both public infrastructure and privately-operated tourism and retailing spaces, using those commercial revenues to pay back the development," Mr Reid said.

Waitomo Adventures chief executive Nick Andreef is the third partner in the venture. With his experience turning the Waitomo Caves into a world-famous attraction, he's been been put in charge of the 'fun' stuff.

"We believe we can create a world-class glow worm grotto experience in the tunnels. We also think that we can have a blackwater rafting experience.

"Finally, we'd like to have a fantasy experience where everything terrible that you could imagine in a cave actually happens. You've got walls that collapse and rooms that flood - and you've got a three metre animatronic troll that will actually get up and kill you - if you're not careful," he said.

Urban advocate Patrick Reynolds, who's been a long-time supporter of rejuvenating the tunnels, believes the project would be such a hit, there'd be no more need for the Auckland Tourism, Events and Economic Development organisation - and we'd never have to market the city again.

"First of all it's a transport route - it's a fantastic way of killing a hill between the bottom of Parnell and the city centre. And then, in the side tunnels there's all the retail opportunities.

"Waitomo Caves have already expressed absolute enthusiasm for putting their little bugs in there. Then there's all the cave-born businesses like fromageries - cheese caves - and wine cellars."

Auckland Mayor Phil Goff is also keen.

"We're supportive of the concept. It's a private sector, commercial proposal so we expect it to be largely self-funding. But we think it has real potential as something that Aucklanders and people around New Zealand would be interested in, but also as part of our tourist trade."

Bill Reid and his colleagues are now hoping for some good news from the company they've approached for funding, and they'd like nothing more than for the tunnels to open before the 2021 America's Cup.

Mr Reid reckons it'd only take six months to get them cleared of rubble and open to the public.