St Mary's Church faces a $978,000 bill to have the building strengthened, but church leaders are determined to see it restored.
The church and hall have been closed since February after parts were found to meet just 10 per cent of the building code.
An initial report noted the buildings required significant earthquake strengthening.
The owner, the Church Property Trustees (CPT), presented a report showing strengthening work of about $350,000 was required to remove its quake-prone status, but an additional $600,000 would be needed to bring the building up to the 67 per cent standard required by the CPT.
Thorough tying of the roof to the walls would bring the church to 45 per cent of the new building standard, according to the Holmes Consulting Group report.
To bring the church to 67 per cent, the west wall would need strengthening, and work is required to link the tops of the marble columns and gables. Code compliance work would cost a further $28,000.
The CPT is still investigating the costs to repair and strengthen the nearby church hall, which has been assessed at 21.5 per cent.
A project manager has been appointed to oversee the rebuild.
Two reports that outline work to bring the building up to 33 per cent and 67 per cent will be completed in a fortnight.
Some of the costs will be met by insurance but the balance will need to be raised by the church.
Vicar Indrea Alexander said until it goes to tender, final figures would not be known.
"There is a lot yet to be done, but we are on track, and we look forward to the eventual reopening of St Mary's.
Restoration Trust chairman Ray Bennett said the trust would keep donors informed of progress.
"There's been so much frustration and delay, and people don't know where we are with the church.
"We're going to make sure that the people who gave money to the restoration trust are well-informed of the present state of where we are with the restoration."
More than $900,000 has been donated towards the restoration project, with most already spent.
The trust had "got a lot of answers" at yesterday's meeting, Mr Bennett said.
"It's been a very frustrating year, but I think we may have made some progress there."
- © Fairfax NZ News