Railway land alongside the Spark Arena is believed to be the frontrunner for a National Stadium in central Auckland, but Victoria Park and Wynyard Quarter are also understood to be in the mix.
The location of six possible sites for a central city stadium costing $1.1 billion to $1.5b have been redacted from pre-feasibility report by PwC for reasons of commercial sensitivity.
However, the Herald understands that the railway land, which Auckland Mayor Phil Goff has previously expressed a preference for, best meets the requirements for sufficient development and operating space for a stadium.
Can the Mayor impose such restrictions of me? Can he really withhold in part a report paid for by ratepayers' money
The railway land, owned by local iwi Ngati Whatua, is on a tight footprint, but is ideally located close to the city's main rail, bus and ferry services, the motorway network, and bars and restaurants.
Other sites put forward by PwC are thought to be Victoria Park and Wynyard Quarter on the waterfront. Retaining Eden Park could be on the list of six sites and the other two sites remain under wraps.
A spokesman for the mayor said he would not comment on any of the possible sites in the report.
It has also emerged that architects Warren and Mahoney have drawn up some high-level concepts of what a central city stadium and precinct could look like.
This was confirmed by the director of venue development strategy at Auckland Regional Facilities, Paul Nisbet, who said the concepts were contained in the redacted part of the PwC report that cost $932,000.
Part of the report that has been made public sets out a rectangular stadium with a retractable roof for rugby, rugby league and football that can be configured for 25,000 spectators at Super Rugby and NRL matches with a curtain on the upper tier to create an atmosphere.
The report shows how the house curtains work at BC Place Stadium in Vancouver.
The National Stadium could seat 50,000 to 55,000 spectators for All Black tests and other big matches. It would become the city's main venue for big concerts, capable of holding 65,000 fans.
The Ombudsman is looking into two complaints against Auckland Mayor Phil Goff over his refusal to give councillors a full copy of the PwC stadium report they can only view at his mayoral office.
Councillor Cathy Casey said the Ombudsman's office had acknowledged a complaint she made yesterday about the mayor's behaviour. Councillor Efeso Collins has made a similar complaint.
In a statement, the Office of the Ombudsman confirmed it had received two complaints and they are currently being assessed.
The Ombudsman has the power to recommend solutions or remedies, which public agencies have a duty to comply with.
Several councillors are livid with Goff for only giving them a redacted version of the PwC report - and making them come to his office to see the full copy.
A mayoral spokesman said it was the first time under Goff's leadership that a commercially sensitive report had not been made available in full to councillors.
He said a number of councillors had seen the full report in the mayor's office and were happy with the arrangement.
In a letter to the Ombudsman, Casey said after being told she could only see the full report in the mayor's office she felt "completely undermined and untrusted as an elected ward councillor Auckland Council".
"Can the Mayor impose such restrictions of me? Can he really withhold in part a report paid for by ratepayers' money?" Casey asked the Ombudsman.
Said councillor John Watson: "It's pretty insulting behaviour. PwC are paid nearly $1 million for this and we are not allowed to have a full copy and reflect on it."