Situated just north of the small Waikato town of Ngāruawāhia, the Military Camp at Hopuhopu was, for Sixty-Two years, the home of the Royal New Zealand Army Ordnance Corps in the Upper North Island.
Located on the banks of the Waikato River and adjacent to the Main Trunk Railway line, at a glance Hopuhopu, in its remote rural location south of Auckland seems a strange place to locate an Ordnance Depot. However, despite its location, the Ordnance Depot at Hopuhopu was significant in the histography of the RNZAOC.
The significance of Hopuhopu was that it was the first purpose-built Ordnance Depot for the New Zealand Army Ordnance Corps, with, at the time of its construction, the most modern Warehousing and Ammunition Storage infrastructure in use by the New Zealand Military.
Purpose-built Military storage infrastructure had been constructed early in the 20th Century at Auckland, Wellington, Christchurch and Dunedin; however, this infrastructure had been built on a small scale to service the pre-war military districts. The Post-Bellum New Zealand Army was in an advantageous position; it had an experienced cadre of men to draw upon to train the building blocks of any future force. Additionally, the Army was flush with enough new and modern equipment to form and sustain an Expeditionary Force of at least one Infantry Division, a mounted Rifle Brigades, Artillery Regiment and Line of Communications troops.
The bulk of the equipment was held by Ordnance at Trentham and Featherston Camps, utilising wartime infrastructure designed to accommodate soldiers and not large quantiles of military material. Smaller amounts to support training and initial mobilisation were distributed to the new mobilisation camp at Burnham in the South Island and the Mount Eden depot in Auckland. Whilst both Trentham and Burnham had room for expansion, the existing infrastructure at those camps was deemed with a few additions, adequate for the time being with no purpose-built infrastructure constructed until 1939/40. However, in Auckland, the depot at Mount Eden was inadequate and unable to support the Northern districts and more robust mobilisation, and storage infrastructure was required.
Storage of ammunition was another concern. Existing ammunition storage across New Zealand consisted of many 19th-century era powder magazines and converted coastal defence batteries, with the bulk of New Zealand’s ammunition supply stored at Wellingtons Fort Balance. These existing ammunition storage arrangements were unsatisfactory, and a more permanent solution was needed in the form of a purpose-built facility.
By 1921 the site of a new Mobilisation and Ordnance Depot to support the Northern Districts had been decided upon, and in one of the largest defence infrastructure projects undertaken in New Zealand, construction of the new camp at Hopuhopu continued throughout the 1920s with the Ordnance Depot opening in 1927. A significant project at the time the progress of construction at Hopuhopu was widely reported on with this Auckland Star article from 1925 describing the plans for the camp;
GREAT MILITARY CAMP
WORK AT HOPUHOPU
DOMINIONS’ AMMUNITION DEPOT
A SPLENDID TRAINING GROUND
Midway between Ngaruawahia and Taupiri, bounded by the railway and the Waikato River, is a long strip of land, some 500 acres in area, level excepting for an extensive hill that rises to an elevation of some ninety feet. This is Hopuhopu, site of the old mission station of the name. Once the home of peace, it is now being transformed by the engineers and men of the Public Works Department into a camp of training for war. Acquired by the Defence Department about three years ago, the Hopuhopu mission site has already been used as a camp for trainees, but it is in the rough, and the plans on which the engineers are now working aim at its conversion into a thoroughly equipped permanent military depot, to be officially known as the Ngaruawahia Mobilisation Base. When the plans are completed, it will be the chief military magazine, for the Dominion, and probably the greatest ordnance depot.
Through the courtesy of the Defence authorities and Mr E. K. James, the engineer in charge of the work, a “Star” representative was permitted to inspect the camp in the making yesterday. The site at once suggests itself as an ideal one for the purpose intended, and this idea is backed by expert engineering and military opinion. There has been some criticism of the area on the ground that it is damp, but this has proved to be a matter that can and will be easily overcome. After heavy rain, there is a degree of surface damp, caused by the matting of thick vegetable growth, but the sinking of a number of test holes has revealed a porous, sandy soil beneath, which, when the “matting” is removed, will readily allow all moisture to percolate and leave a dry surface. In fact, the site lends itself readily to perfect draining. About one hundred men are engaged in the work of clearing and building, and they have been greatly hampered in their preliminary operations by the amount of furze and blackberry that ‘successive owners of the land (including the Government) have allowed to grow on it. The furze is not so hard to clear, but an instance of the pertinacity of the blackberry was shown in a patch that was again springing to vigorous growth two months after it had been cut. Over one hundred acres have been cleared, and there remains another 150 acres to be dealt with by hook and fire.
A Varied Terrain
The great value of the Hopuhopu site is that it is adaptable to every branch of military training. A detraining platform a quarter of a mile long will be constructed on the main railway line for the embarkation and disembarkation of troops; there are large level areas for parade grounds; there are hills for reconnoitre and signalling; there is the river for bridge-train and pontoon drill, and in fact, the contour of the country will enable training in every department of military tactics. When the camp is completed, its huge stores, magazines and hutments will spread over an area of 200 acres. It is proposed to provide sanitary drainage from the latrines by a large pipe running along the railway into septic tanks, and thence into the river. The first part of the plan provides for the accommodation of a full battalion, and this will gradually be extended to mobilise and house a brigade of about 5000 men. Next year trainees of the Northern Command will sleep beneath the roofs of solid huts, instead of in tents.
In arriving at the decision to construct this great camp at Hopuhopu, the authorities were doubtless influenced by other considerations additional to the natural suitability of the site for training purposes. It is a reasonable distance from the city; yet not too near. It is not advisable that men in training should have the temptations of a city that is in too close proximity, and it is essential really that a camp containing immense stores of ammunition should be out of range of shelling by a possible hostile fleet operating, for instance, in the Hauraki Gulf. Besides, Hopuhopu is a very handy site for the mobilisation of the thousands of trainees who reside in the closely settled districts of the Waikato.
Some acres of the campsite, between the Old South Road and the river, have been reserved for residences for officers of the permanent staff, the building of which has already been commenced in the corner adjacent to the railway, line. These houses are being constructed of concrete. The whole of the ordnance department is to be transferred to the camp, which will take over a great deal of the stores now housed at Featherston. The extent of the future ordnance department at the new base may be gauged from the fact that the plans provide for five sheds measuring 40 x 500 ft, 40 x 300 ft, 40 x 200 ft, 40 x 100 ft, and 40 x 350 ft. These will lie alongside the camp railway, which runs into the camp for a distance of half a mile from, the mainline, so that stores may be received and dispatched with a minimum of labour and a maximum of speed. From the terminus of this extension, a wooden tramway is to be constructed to the foot of the hill along the base of which the magazines are being built.
The Magazine Section
No fewer than ten magazines for the storage of explosives and ammunition are provided for, and several of these are nearing completion while excavating and banking is being carried out on the site of the great laboratory to be attached to this department. The magazines are built into the hillside. They are constructed of concrete, with double walls, in between which are formed the inspecting chambers. From these chambers’ sentries may see through observation windows the thermometers which register the temperature inside and by this guide check or increase ventilation, as needed, for the explosives must be kept at a certain degree Fahrenheit. Also, the double-wall is a protection against fire. Between each magazine, a pyramid is erected from the spoil taken from the excavation. These are eave high with the roofs of the magazines and are designed to break the force of any possible explosion of one magazine, so that others may not be exploded also. The magazines are also faced by a long embankment, and are, of course, backed by the hill, so that an explosion would be confined as far as possible to the magazine area.
On top of the hill, there has been constructed an 80,000-gallon reservoir for the camp water supply. The water is pumped by a 30 hp motor from a settling tank alongside the river and ten feet below the level of its bed. The water is well filtered and regarded as pure after it has percolated into its tank, but as an additional safeguard, a chlorinating plant is to be installed.
Negotiations are proceeding with landowners on the other side of the river for the acquirement of land for a rifle range.“Great Military Camp,” The Auckland Star, vol. LVI, no. 83, p. 5, 8 April 1925.
The Ordnance Depot opened in 1927. The original plan called for five warehouses measuring 40 x 500 ft, 40 x 300 ft, 40 x 200 ft, 40 x 100 ft, and 40 x 350 ft; what was eventually construed was a single large warehouse measuring 100 x 322 ft.
An additional Ordnance warehouse was constructed adjacent to the original building during the Second World War. The wartime era also saw the nationwide expansion of the NZ Army’s Ammunition infrastructure with additional magazines added to the existing ten magazine at the Hopuhopu Storage area and a new Ammunition Depot established outside of Hopuhopu Camp at the nearby Kelm Road.
Hopuhopu and its Ordnance Depot survived until 1989, when as part of many rationalisations taking place across the New Zealand Defence Forces, Hopuhopu camp was closed, and its functions passed on to other locations.
 Mark McGuire, “Equipping the Post-Bellum Army,” Forts and Works 2016.
 “Great Military Camp,” The Auckland Star, vol. LVI, no. 83, p. 5, 8 April 1925.
 Furze is another term for gorse.