The preferred option for a new roofed arena in Christchurch is for a retractable pitch and will come in at nearly half a billion dollars, according to a feasibility report.
The government has released the report, which looks at a potential long-term replacement for Lancaster Park - damaged by the 2011 earthquake.
It has bought land across three blocks near the CBD for the arena, but no further progress has been made.
A covered arena is wanted, given Christchurch's winters.
The two options which met potential users' criteria were:
* A 25,000-seat arena with a transparent roof. Estimated cost $465 million
* A 25,000- seat arena with a solid roof and retractable pitch. Estimated cost $496m
Capacity could be increased by 5000 temporary seats.
The feasibility report, by the Christchurch Stadium Trust, says if there was a preferred option it was the $496m model.
"The versatility, potential utilisation and event opportunities this option offers presents a positive financial performance," the authors said.
"The retractable pitch provides the character of an arena as opposed to a stadium, which is still the predominant mode of (Dunedin's) Forsyth Barr Stadium."
The other two options were a 30,000-seat arena with a solid roof and retractable pitch for $584m and a 25,000-seat arena with 75-80 per cent roof cover for $368m.
A 30,000-seat stadium was less than NZ Rugby and Canterbury Rugby wanted but neither would contribute to building costs. Concert promoters also wanted up to 40,000 seats.
The council had $253m in long-term funding plans for the project and the balance could come from a regional rate. Debt funding and pre-sales of commercial rights weren't ideal, the report said.
Minister supporting Greater Christchurch Regeneration Nicky Wagner says the next step is to decide on a preferred option and further develop the business case.
"Any option must be an asset for Christchurch, Canterbury and New Zealand. That means generating revenue, but it also means embracing innovative trends and new technologies."
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