The Police and Convict Building was designed in 1833 by John Lee Archer and built between 1835-1836. The ground floor contained a number of cells which were removed in 1860, after the Police and Gaols Department moved to Campbell Street and Treasury moved into the building. The basement is still intact containing the original watch house with fire place, two additional rooms and a large cell, with slit windows visible from the exterior.
The central building on the Murray Street frontage was designed in the old Georgian Style in 1837 by John Lee Archer to join the 1824 Court House with the 1835 Police and Convict Building. Archer was retrenched in 1838 and so it was Alexander Cheyne, head of the newly formed Department of Public Works and his second-in-command, James Blackburn (a convict) who reworked Archer's design and oversaw construction. It was James Blackburn who designed the four columned portico at the Murray Street entrance.
The basement was designed to provide fireproof storage and rooms for the messenger and court keeper. It was originally connected to the ground floor by a narrow staircase, which was later removed.