Auckland Council has thrown its weight behind an ambitious proposal to reopen and renovate a network of WWII tunnels lying beneath Auckland's CBD.

On Tuesday Auckland Council's planning committee unanimously backed a proposal to turn the dilapidated air raid tunnels beneath Albert Park into a "subterranean city", complete with cycleway, glowworm attraction and privately owned businesses, like a wine cellar.

It was supported by all councillors, including Auckland mayor Phil Goff.

The 3.5 kilometres of tunnels, which were built to keep up to 22,000 people safe in the event of Auckland being bombed, have been sitting idle since they were sealed off just after the war.

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The main tunnel, running from Victoria St East in the CBD to Beach Rd in Parnell, is 4.4 metres wide and 3m tall and lined with timber beams.

JAMES PASLEY/STUFF Bill Reid's 30 year dream to open Albert Park Tunnels might be nearing its end.

Bill Reid, who has worked on reopening the tunnels for the past 30 years, and his business partner Nick Andreef, propose converting the tunnel into a pedestrian and cycleway link between the city, University of Auckland and Parnell with two sets of elevators connecting the tunnel to Princess St and Symonds St.

The tunnel restoration, estimated to cost up to $19 million, would effectively be an extension of a concourse to Aotea Station, being built as part of the City Rail Link.

Reid said the project had received support from both the University of Auckland and Auckland University of Technology.

JAMES PASLEY/STUFF Beneath Albert Park 3.5 kilometres of air raid tunnels have been sitting unused since they were blocked up after WWII.

Transport planning consultant Nicolas Reid, no relation to Bill Reid, said it was estimated about 4000 people per day would commute through it to access the institutions.

"If you attempted to deliver something similar by building a new public transport system of equivalent capacity, you'd be looking at millions of dollars," Reid said.

Auckland councillor and planning committee head Chirs Darby said the concept was "without a doubt" very interesting.

SUPPLIED The tunnels are lined with timber beams.

"Imagine walking through from the city centre via this shortcut to the museum, let alone everything else in between connected to the university," Darby said.

A promise from Reid that the project would be privately funded and council would incur little to no cost was an appealing aspect, he said.

"We are even more engaged on that."

SUPPLIED Workers in the Albert Park Tunnels, circa 1942.

Councillor Desley Simpson said she was joining a long line of people who think the concept was a "wonderful idea".

Getting formal approval from the Waitematā Local Board will be the next step for the project, as this is required before resource consent can be granted.