The plan to redevelop the Sarjeant Gallery Te Whare o Rehua is estimated to cost $34m and key to the project have been efforts to raise $10m in private funding to unlock a matching amount from central Government through the Ministry of Culture and Heritage's Regional Culture and Heritage Fund.
If everything goes to plan construction is due to begin next year, enabling the historic gallery to be reopened in time for its centenary celebrations in 2019.
In August Nicola Williams, chairwoman of the Sarjeant Gallery Trust, said a combination of donations, pledges and bequests had taken the fundraising to just over $10m which meant the trust could lodge an application with the Ministry for Culture and Heritage.
Ms Williams said if government funds were approved the trust was confident of raising a further $9m by the end of the year to complete the project fundraising.
On Saturday the public was able to tour the existing gallery and walk through an installation dubbed The Blueprint, which is a surveyed, to-scale layout of the gallery extension on site in Queen's Park. A cherry picker will take people up to the height of the proposed viewing window at the back of the gallery.
The redevelopment of the Sarjeant involves restoration and earthquake strengthening of the original building, and the addition of a new, state-of-the-art gallery. The new wing will provide storage for the art collection along with additional gallery space, education facilities and a cafe.