Most of Albert St in central Auckland stands to be dug up and more than 200 properties affected by the city's proposed $2.86 billion underground railway.
According to a plan announced by Auckland Transport yesterday, most of 210 surface properties likely to be needed for the project are at the Mt Eden end of a 3.5km pair of tunnels running under the west of the city centre, from Britomart.
They will include the five-storey headquarters of MediaWorks and its TV3 subsidiary below the New North Rd and Mt Eden Rd intersection, near where the tunnels will emerge before joining the western railway line.
But an even larger property in the firing line is Westfield's sprawling Downtown shopping mall of 81 retail outlets at the city end, valued at more than $80 million.
Auckland Transport chief executive David Warburton said the site would probably have to be cleared for a pair of "cut and cover" trenched tunnels from Britomart to upper Albert St, behind Aotea Square.
That may fit in with redevelopment plans yet to be determined by Westfield, which holds a resource consent to build an office tower. The company said yesterday it was not in a position to comment in detail on any future deal with the transport body's Auckland Council parent.
From near Albert St's intersection with Wellesley St, double-tracked railway lines will be laid through deep bored tunnels to Mt Eden, passing under Pitt St, Karangahape Rd, the central motorway junction and Symonds St.
As well as surface properties at each end of the rail link, underground portions of land in 70 titles including 12 with multiple owners will need to be bought for the tunnels and three stations beneath upper Albert St, Pitt St and Symonds St.
But although land purchases have been estimated to cost $231 million in today's dollars, Auckland Transport expects to recover more than half the money from reselling properties after completing the project by 2021.
The council body has written to affected land owners before seeking a formal route designation by the end of this year, saying their properties are within the project's "footprint".
Although the Government has not yet agreed to contribute to the project, for which Mayor Len Brown gained the highest priority of any transport scheme in the 30-year Auckland Plan, Dr Warburton said it supported route protection measures.
His organisation had ruled out boring tunnels beneath Albert St, because these would be too shallow, but hoped to keep excavations for a covered trench "predominantly in the road corridor". He could not say for how long the busy bus and general traffic route would be affected within a five-year project period.
Acting council transport chairwoman and former Auckland mayor Christine Fletcher, who leads the right-leaning Communities and Residents group, welcomed the route protection moves but remained firm that construction should not start until funding could be identified.
Heart of the City business group chief executive Alex Swney said the project may prove more transformational for Auckland than the harbour bridge in doubling the rail network's capacity, for which traffic disruption in Albert St was an unavoidable part of the price.
"Britomart will be at capacity under current trends by 2020, so doing nothing is clearly not an option," he said.
But Automobile Association spokesman Simon Lambourne, although agreeing that a route should be protected, said his organisation questioned whether it should run under Albert St rather than closer to the growth area of Wynyard Quarter.
* 3.5km pair of tunnels from western end of Britomart to Mt Eden, to a maximum depth of 45 metres.
* To cost $2.86 billion (in inflated 2021 dollars).
* Cost includes three underground stations and 50 more electric trains (extra to 57 already on order).
* Five year construction period, from 2015-16 to 2021.