Pete Gray, council deputy community and cultural manager, told the Chronicle that the resource consent application would be lodged as soon as possible after the Christmas break, and that an IL3 build standard would achieve the same level as the Christchurch Art Gallery.
The Sarjeant Gallery Te Whare o Rehua Whanganui is one of the country's foremost art museums.
It was founded 100 years ago through the generosity of local farmer Henry Sarjeant, who left the equivalent of $75 million in his will to found a gallery "for the inspiration of ourselves and those who come after us".
Today there are more than 5500 artworks at the Sarjeant and its New Zealand collection is recognised as one of national significance, holding a comprehensive number of artworks from 1840 to the present day.
Mr Gray said the importance of the gallery and its collection was underlined by the "strong encouragement" the Minister for Arts, Culture and Heritage, Chris Finlayson, had given to plans to redevelop the Sarjeant, protecting the building, looking after the collection and enhancing access.
"This is why the minister has set aside $10 million to support the project," he said.
The council made its first application for funding to the ministry in May 2012 but it has been this issue of securing government funding which has been at the nub of much of the debate.
Opponents to the project said Mr Finlayson had never given an absolute commitment regarding ministry funding, while others argued he was clear in his offer.
Even as late as November, the minister wrote to Mayor Annette Main, saying he could not grant government money to the project because more detailed "evidence" was needed.
Last year, the ministry was telling the council that resource consents, detailed architectural and engineering designs and costings were needed, along with evidence that "significant" fundraising had been achieved.
Yet despite those shortcomings, Mr Finlayson said he regarded the strengthening of the existing gallery and its extension as a funding priority and he had instructed his officials to "build and hold sufficient funds in reserve" so he can "expedite" his final grant decision.
He wanted to see the project earn that $10 million in government funding "during my term as minister", and he hoped the incoming council would move quickly to get the initial steps under way and "publicly establish their united position on supporting this project so that its external fundraising campaign can move forward quickly".
But more telling is Mr Finlayson's closing remark: "As I said last year - attend to the issues I have raised ... and the funding you are seeking will be available."
The options facing the council are either strengthen the existing gallery or combine the strengthening with a new extension to the gallery (the redevelopment project). Costs for the redevelopment are estimated at about $28 million, while quake-proofing the gallery only has been costed at $16.8 million.
Not only is there a considerable gap between those estimates but there is a major shift in where funding for those two options would come from.
For the redevelopment, the council would rely on financial support from the Ministry of Arts, Culture and Heritage ($10 million), Lottery Commission ($3.5 million), trusts ($1.970 million), corporates ($7.5 million) and a further $700,000 from "other lottery funding".
Fundraising from the local community has been estimated at $1.94 million, with the final $2.5 million coming directly from the council. If the council drops the redevelopment and concentrates solely on quake-proofing the existing gallery, then $13.5 million of that $16.8 million price tag would have to be conjured up by the council. It would also have to rely on $2.5 million from lottery funding, $500,000 from trusts, with another $250,000 coming from community fundraising.
Consultants Brent Wheeler Group were commissioned to measure the benefits of the gallery's redevelopment - in other words, ascertain if the cost of the project was going to produce net benefits for Wanganui. The consultants said that over the life of the redeveloped Sarjeant Gallery the net value to the community was in the order of $95-$105 million.
They also concluded that it was "difficult to see any other single project which is likely to offer this level of benefit".
Whatever path the council finally heads down, the issue of protecting staff, the collection and the public, remains a priority that quake-proofing the gallery will cover, one way or the other.
That is why the council had to look for a temporary home for the gallery while the Queen's Park building was either strengthened or strengthened and extended. It has arranged to lease space at 38 Taupo Quay and 17 Drews Ave, a property being developed by Quay 11 Ltd.
Mr Gray said strengthening work on the Taupo Quay site had been completed and the construction of the link building - housing the lift and education room and connecting 38 Taupo Quay with 17 Drews Ave - was about to begin.
"The gallery will close to the public on March 2 next year and that is when offices, front-of-house, workrooms and the education room will be packed up and moved to the Taupo Quay building," he said.
"The Sarjeant will reopen at 38 Taupo Quay, with new exhibitions and education programme in May."
As for the design phase of the project, Mr Gray said that process was under way.
An internal council team was involved but the design will be undertaken by external professional firms, with Warren & Mahoney the lead architects.
The council has spent about $130,000 so far on the relocation and a similar amount on the redevelopment project.
If all goes to plan - assuming the council secures that external funding from both government and major sponsors - Mr Gray said the redeveloped Sarjeant could reopen in 2019, in time to celebrate its centennial.