The clocktower building was one of the first structures to be built for the Trentham Military Camp.

Before the First World War Trentham was primarily used for summer camps and training in association with the Trentham Rifle Range (established 1892). On the outbreak of the First World War Trentham became a mobilisation camp, with most of the accommodation areas under canvas. In 1915 work began on the construction of permanent buildings under the direction of the Public Works Department. The history of the clocktower building is confusing. Camp records suggest that the building was erected in 1916 for an Anglican church. It is more likely, given the presence of tiered seating, that the building was erected as a cinema to entertain the members of the First New Zealand Expeditionary Force who received their training at the camp before being shipped overseas. After the war activities at the camp were scaled down and during the 1920s the cinema was converted into a sailmaker's hut. In 1943 it was converted into a lecture hut and in 1948 the south end of the building was converted into sleeping quarters. The building now serves as the library and convention centre of the military camp.

The main building is a rectangular timber structure with a broad gable roof. It has lean-tos on the east and west elevations. The most striking feature of the building is a three storey square tower, on top of which is placed a clock in a small cubic turret. The clocktower is considered to be in original condition, though the clock is now run by an electronic mechanism. There are double-hung sash windows on all elevations. The building is clad with weatherboard and has a corrugated iron roof.

The Trentham Military Camp Clocktower is significant as one of the original camp buildings. Although modified internally, its exterior has changed very little, and the building has remained an important camp landmark.