The first extensions were made to the rear of the building in 1947 to provide more office space for members. Some further extensions were constructed in 1964. In the 1970s large extensions were added to both sides of the building and the south-west corner. The front façade was extended in a sympathetic fashion to conform with Murdoch's design. On the Representatives side, larger extensions were required, and a substantial part of the gardens were built over and linked to the main building by a bridge.