The Auckland Council plans to buy up to $230 million of property for its still uncertain downtown rail tunnel.
The council's transport agency on Tuesday announced that up to 210 properties will be affected along the proposed route from the Britomart terminus under Albert Street in the central city to the suburb of Mt Eden.
Twin rail tunnels would be built. The aim is to provide three new downtown rail stations and boost the frequency of trains serving the city by creating a loop. It is hoped the project will be completed in 10 years.
Auckland Transport says not all of the identified properties may need to be purchased and talks will be held with owners over coming months.
It says the final property cost may fall to about $90 million after some are re-sold once the tunnel is completed.
The biggest single property affected is the Downtown Shopping Centre, which will have to be demolished. TV3's headquarters in Mt Eden is also in the way.
Alex Swney, chief executive of business group Heart of the City, says the proposed rail scheme is one of the most transformational transport projects in Auckland's history.
Mr Swney told Radio New Zealand's Checkpoint programme on Tuesday there has been no commitment to public transport - and something has to change.
"We've got a city that's got more cars than it's got licensed drivers. We've got sprawl second only to Los Angeles. We're at a point where we've got bus congestion. We're reaching a point where Britomart is acting as a terminus rather than part of a network at the moment."
Planning and property acquisition will take several years, in which time Auckland Council will try to persuade the Government to share the $2.4 billion cost of the project. Property purchases will begin in 2014.