Auckland's historic St James Theatre could cost $60 million to $70 million to restore.
Steve Bielby, principal trustee for the building's developer, the Auckland Notable Properties Trust, said those were the estimates for a full restoration. Funding was yet to be secured but he was optimistic it could be sourced.
"The owner has some obligation," Mr Bielby said, referring to Relianz Holdings, which bought the St James last year. "But there's going to need to be public funding for this.
"We're close to closing the gap between the owner's funding and the public. We've been talking to Auckland Council, the Government, trusts - everyone. There will need to be a contribution from a large number of parties."
Noel Reardon, Auckland Council's heritage manager, indicated the Super City's financial contribution was unspecified.
"Auckland Council is working closely with the owner of the theatre. The council will be receiving a report on the project in October. The council is committed to supporting the restoration. The detail of the funding will become more apparent once councillors consider next month's report," he said.
Heritage campaigner Margot McRae has described the St James as New Zealand's Albert Hall and produced a 50-minute documentary on the 1928 theatre.
George Farrant, the council's central principal heritage adviser who is on loan to the project, said work on the Category 1 building could be carried out in stages, making it more financially manageable.
Mr Farrant cited the Civic's $41.8 million restoration, "which equals $62 million in today's dollars. But we will get there. Long term, the outlook for funding is good."
He had found pictures of the Civic Theatre in Newcastle, Australia, which was virtually identical to the St James but with two levels of seating, not three. That building was by the same architect, Henry Eli White.
Relianz is developing the front of the St James site, building a 39-level, 300-unit apartment tower costing $175 million, and Mr Bielby said all apartments had now been pre-sold.
Mr Farrant said a restored St James might be ready to reopen by 2017 or 2018, he said. A cafe in the foyer, open from 11am to 2pm, will soon close when more extensive works start.