The Hall of Memories at the National War Memorial in Wellington is closed for earthquake strengthening work.
The Ministry for Culture and Heritage says the work is the result of an initial assessment made after the magnitude 6.5 earthquake on 21 July.
It shows the building's strength falls short of building code standards.
Chief executive Lewis Holden said it is vital the hall is safe as it will play a crucial role in the centenary of Anzac Day in 2015.
A report has been commissioned which will provide options for the strengthening, and the time and effort required to do so.