The transformation of Western Springs into a test cricket oval and AFL venue will come at a significantly increased cost.
As revealed in Friday's Herald, the central Auckland venue is the probable future home of test cricket in the Queen City, eventually likely to supplant Eden Park.
But it's believed that the cost of the upgrade and redevelopment of the arena has increased five or six fold from the initial $12 million tabled in 2014.
The Herald on Sunday understands that a figure of up to $70 million has been proposed to various stakeholders by Regional Facilities Auckland, the council-controlled organisation that manages Auckland's stadiums.
There have been several other important developments in Auckland's ongoing stadium jigsaw.
• The RFA hope to confirm the future home of speedway in the next few months, with the motorsport due to move from Western Springs in April 2019.
• Test cricket could be played at Western Springs within two years of speedway moving out.
• The RFA is confident of securing a deal for up to three AFL matches a year at Western Springs.
• The Warriors could move out of Mt Smart before their lease expires in 2028, but only if another suitable alternative venue can be found.
But it's the cost escalation at Western Springs that will raise the most eyebrows. The original upgrade proposal - which was passed by council in 2015 - was $12 million but the revised figure will be much higher.
"We are still working through that," said RFA CEO Chris Brooks. "We are getting some planning done and we are probably a month or two away from getting the numbers."
Brooks agreed there would be a sizeable increase from the initial proposal.
"That's possible," said Brooks. "Since we have revamped the stadium strategy we have probably changed our thinking a bit. The original $12 million was for an international cricket oval [and] there was potential for a staged process. It was future-proofed for future stages if required. That is what we are working on with the stakeholders. We are not quite there in terms of all our planning [and] what you do in terms of seating, corporate areas etc."
Auckland has only hosted two cricket tests in the last decade, but the RFA is hopeful of up to two each summer.
However, speedway's future destination is still unconfirmed, with their current lease expiring at the end of March 2019.
"We have been working with speedway about what's next after Western Springs," said Brooks. "They recognise that if they are going to grow the sport they have to find a venue that they can use on a more regular basis. Those discussions are under way as to what those options are."
Colin Dale Park in Manukau has been touted as one option, though its suitability has been questioned, while Brooks said there was another (undisclosed) venue under consideration and the RFA was "hopeful of finalising the decision in the next few months."
Springs Speedway spokesperson Greg Mosen is keeping an open mind.
"We are in the middle of our best season in years," said Mosen, who projects a cumulative attendance of 120,000. "We have been here 88 years - that's longer than the Farmers Christmas Parade has been going - and it's a great venue. But we want a long-term solution and if it is viable we are all ears."
The RFA estimates that the full transformation of Western Springs will take two years beyond speedway's exit, though the cricket oval itself could be completed in six months.
AFL is also a key component of the plan, with Brooks' vision for regular season matches in Auckland.
"Auckland is part of the AFL's international strategy," said Brooks. "We have had really good discussions with them and St Kilda. We would be hopeful of getting two or three games from St Kilda on an annual basis."
Although AFL didn't last in Wellington - crowds dived after the first year's novelty value - Brooks is optimistic.
"Auckland is an entirely different proposition," he said. "There is a bigger population base, better flight connections and the AFL are keen to fully support and invest."
The final piece of the jigsaw, according to Brooks, is a "national football stadium", where rugby, league and football could be housed. The debate will boil down to a new stadium - perhaps downtown - or pouring yet more hundreds of millions into another Eden Park makeover.
"The city needs to look at where it makes its next investment into a rectangular stadium," said Brooks.
If that eventuates before 2028, the Warriors could be on the move before the end of their current lease.