There is evidence to suggest that the Cowley Beach site near Innisfail was used for military equipment testing as early as 1954. Previously, Australia had been testing equipment in hot/wet tropical conditions on Los Negros Island near Papua New Guinea. The Cowley Beach site was chosen because of its high temperature and high humidity, and the exaggerated combination of these factors in the wet season.
The Tropical Trials Establishment had other sites as well as Cowley Beach, the gazettal of land acquired at Tully in North Queensland occuring in 1967 (Commonwealth Gazette, No.50, 15 June 1967 p.2998 and map facing page 2998).
The Tropical Trials Establishment became an independent establishment in 1969 responsible to the Directorate of Trials and Evaluation at Defence Headquarters.1
Its functions involved the measurement of the effect of the tropical environment on military equipment, including stores to full scale operational evaluation of complete weapon systems.
There is no reference to the Tropical Trials Establishment until the Commonwealth Directory of 1977 (p.93). The Officer Commanding is given as Major K.E. Melrose.

The functions of the Tropical Trials Establishment were taken over
by the Joint Tropical Trials Research Establishment (CA 2798) on 24 October 1977.

References:
1. "Coping with Climate" in 'Triad, A Defence Magazine', No.11,p.15.  

Historical agency address
Cowley Beach via Innisfail, Qld

Superior agency unregistered

Directorate of Trials and Evaluation, Army Headquarters