The land on which this building was built was originally part of an area reserved for the public buildings of the General Government in 1867 (Gaz. 1867 p.374.). This Block became the local administrative centre with the County Council Offices, the Post Office, the Warden's Court, the Jail, the Postmaster's House, and Police staff houses all within the same area.

The 1866 building was occupied as Warden's Court from 1866-1876. In October 1876 it was handed over to the control of the postmaster general. The Post Office took up occupancy in 1877, moving from its older building which was situated behind the present one. The building remained the home of the Post Office from 1877 to 1973. In 1973 the Post Office shifted to new premises on Ross Place, and the building was vacated, and has remained largely unoccupied, except for a few short term tenancies since.

By the mid 1970s there was discussion about creating a historic reserve, noting the Post Office's importance to the other historic buildings in the vicinity, notably the adjoining Warden's Court (c.1874-1876), the Lodge St George (1878), the Presbyterian Church (1886) and other associated government buildings on the wider block. The site was reserved for historical purposes in May 1979. The Commissioner of Crown Lands at the time noted that the building was a landmark, "not only in Lawrence, but from the point of view of early New Zealand architecture," and hoped it would be put to good use by the local community. The property was handed over to the NZHPT to administer under the Reserves Act 1977 in mid 1981.

By the mid 1980s the building had remained untenanted and suggestions were made to revoke reserve status and sell it, with a covenant in place to protect it. The Reserve status was revoked, and the building sold into private hands in November 1989. A Heritage Covenant was registered on the building in 1990 (document 760813).