During the building boom of 1885, the former convict Officers' Quarters and Military Barracks was selected the site of the new Brisbane Treasury Building. The military moved from the existing buildings and they were occupied by the Registrar-General, Treasury and Engineer of Harbours in 1864. The Registrar-General’s single-storeyed building was erected on the corner of George and Queen Streets In 1874.
In 1883 the colonial government decided to construct new public offices on Treasury Square and the Queensland Government stated it was anxious to get as perfect a design as possible and offered prizes for the three best designs. Architects from the various colonies submitted plans for the proposed building.
In 1883 a design competition for a two-storeyed building was won by Melbourne architects Grainger and D'Ebro. However this design was never used as the Queensland Colonial Architect, John James Clark, argued that the site warranted a four-storeyed complex. Clark's own design, entered in the competition prior to his appointment, was used.
Liverpool trained architect John James Clark, who designed the Yungaba Immigration Depot, was the chosen design of one of the then largest public buildings in Australia. The design can be described as Classical Revival style, with facades having a mix of Ionic, Doric and Corinthian columns. Italian Renaissance style colonnades protected the interior from direct sunlight and rain.
Three stages of construction went into the completed treasury building, starting with the William Street frontage. Planning for the first stage of the Treasury Building, which fronted William Street and the Brisbane River and was completed by the middle of 1885, and the site prepared. Tenders were called in April 1886, and Sydney builders Phippard Bros & Co. were successful with a price of £94,697/10/- and completed this section in 1889.
This was the new centre of government administration in Queensland was occupied by the Premier, Colonial Secretary, Registrar-General, Treasury, Mines, Works, Police and Auditor-General. It was home to the Cabinet and frequently to the Executive Council from late 1889 to 1905. To protect the valuable records, the Registrar-General’s office was fire proofed.
When first stage of the imposing Brisbane Treasury Building was completed it met with the satisfaction of the Government. Clarke's reputation increased and he eventually was lured to work in Melbourne and never returned to Brisbane.
Stage two completed the Elizabeth Street section and continued two-thirds of the way along the George Street.
Documentation and working drawings were prepared by Thomas Pye, employed to supervise the project and tenders called in April 1890. The principal contract was let to builder John Jude of Adelaide, with a contract price of £67,000.
Completed in February 1893, the new wing was occupied in the middle of that year by the Registrar of Titles, Justice, Works, and Public Instruction. The State Savings Bank had a purpose-built banking chamber included in the design. The courtyard was landscaped with grass oval surrounded by a carriageway. Serving as a symbol of self-government it was the focus for celebratory displays including the 1901 proclamation of the Australian Commonwealth.
The construction elsewhere of new offices for the Department of Agriculture and the Executive Building provided additional government accommodation and work on the third stage was not started until 1922. The Registrar-General's building was demolished late 1922 and construction of the George and Queen Street facade commenced in 1923. The front elevation differed slightly from Clark's original concept.
Structurally it was a 1920s building in internal materials and fittings. Completed, occupied and opened officially in 1928 at a final cost of £137,817, it provided expansive space for the Treasury Building tenants.
The base of Treasury Building Brisbane, is constructed from Brisbane tuff and Queensland sandstone quarried at Helidon, Highfield and Lockyer completed the four floors and the facades above. A photograph of a model of the completed Treasury building incorporates a tower which was never completed.
After 40 years after its completion, the exterior needed cleaning and restoration. Restoration work included marble steps to the main Queen Street entrance and repairs to the stonework and re-pointing. Demand for further accommodation In the 1950s, led to the construction in 1961 of a five-storeyed annex in the courtyard.
The Treasury Building Brisbane became outmoded as suitable office accommodation and in 1971 the Treasury and Works Departments moved to the new Executive Building at 100 George Street. A Government proposal in the 1990s to convert the building into a Casino met with some objection. Conversion of this magnificent building into the Brisbane casino has ensured that Clarke's creation and Brisbane's most imposing building has been saved for posterity without the need to spend Government money on its restoration.