AR9 Fuel Bunker
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Cambridge’s Wartime Secret: The Hidden Aviation Fuel Depot
Built in 1942, this secret aviation fuel depot was part of New Zealand’s wartime defenses. Hidden beneath the hillside, a vast underground tank once held 600,000 gallons of fuel for the Royal New Zealand Air Force (RNZAF). The tank was drained in 1946 and removed in 1950, while the pump house was sealed in the 1970s. Recently restored so you can peek inside, the bunker offers a glimpse into Cambridge’s hidden WWII history.
Aerial view of hillside near Lake Te Koo Utu where there used to be a WWII Fuel Bunker Source: Lucy ROWDON CM4345
Why Cambridge?
During the war, aviation fuel was as valuable. Airfields were obvious targets for attach, so the RNZAF created a network of hidden storage sites around the country. Cambridge was chosen as one of these secret depots because was close to the main RNZAF base at Rukuhia (today’s Hamilton Airport), yet far enough away to be safe from attack.
Building the Depot
The work was carried out by Public Works Department men who were also building the Karāpiro Hydro-Electric Dam. Local man Jim Wilkinson remember watching the AR9 being built To keep the tank hidden from enemy planes, fast-growing gum trees and shrubs were planted to provide natural camouflage. A railway siding (now Lakewood) allowed fuel trains to pull in quietly and empty their tanks. Most likely this happened at night, under the cover of darkness. From the tank, the fuel travelled downhill through a concrete tunnel and pipeline to waiting trucks by the lake. These trucks then delivered the fuel to Rukuhia, where it kept the Air Force’s flights in the air. (Source: AF9 Fuel Depot, Wings over Cambridge – AR9 https://www.cambridgeairforce.org.nz/AR9%20Fuel%20Depot.htm)
A Tragic Fire
The secret site was guarded day and night by armed airmen. But on 14 October 1943, tragedy struck. A fire broke out in the small barracks hut where the guards slept. The likely cause was a cigarette. Leading Aircraftman Richard Edward Isaacs, just 20 years old, was killed. He was later buried in Karori Cemetery, Wellington.
Inside the AR9 Fuel Bunker, 2121 Source: Lucy Rowdon CM4345
Rumours and Legends
After the war, the site was abandoned and stories grew up around it. Generations of Cambridge children knew it as “the bomb shelter.” Others spun taller tales, claiming the tunnel ran all the way to the Town Hall to allow the mayor to escape in an air raid, or that it emerged under Fort Street at the so-called “goat shelter.”
None of these stories are true. In reality, the tunnel only ran a short distance underground, carrying pipes up to the fuel tank. But the air of mystery has lingered for decades.