Unlike the proposed demolition proposed in the 1964 scheme, the 1972 development plan required the new building to be constructed entirely within the boundary of the existing site, while leaving space for future additions to the State Library of New South Wales. Added to this restraint the work of the Parliament needed to continue through the entire construction period.
The 1972 development plan differed from the 1964 demolition proposal by requiring the new building to be built entirely within the existing site, while still allowing for future additions to the State Library of New South Wales.  This restriction was also accompanied by a need for Parliament's work to continue throughout the construction process.