List of Official Investigations into North Head / Maungauika

List of Official Investigations into North Head / Maungauika

There have been more than a few investigations into the mysterious mist of rumour and secrecy that has settled on North Head / Maungauika over the years. Curiously, none of the investigations have actually fully excavated any areas of interest where hidden tunnels are suspected to be located.

Earnshaw and friends

Brief descriptions of each investigation are below, but more detail on each can be found in Martin Butler's book 'Tunnel Vision'.

  1. Pre-1960 — George Bolt's informal investigation
  2. 1980 — First formal military investigation
  3. 1984-1988 — John Earnshaw & NZ Army
  4. 1992-1994 — David Veart & Department of Conservation
  5. 1996-2001 — Court Cases: John Earnshaw vs Crown
  6. 2010-present — Martin Butler's 'Tunnel Vision' investigation 

Pre-1980 — George Bolt's informal investigation

A few civil inquiries and minor inspections were made over the years prior to 1980.

After the New Zealand Flying School was closed in 1924, the original Boeing 1 aircraft were slowly forgotten. But not by George Bolt and his friends in the Royal Aeronautical Society. In the mid-1950s George Bolt and Doug Patterson, Chairman of the National Airways Corporation, started actively trying to track down the missing aircraft. 


Reports surfaced that aircraft had been stored in the tunnels at North Head, including the Boeings. Some, but not all, were recorded to have been burned on the beach nearby. After combing the location, metal aircraft pieces were sent to Boeing and identified as not Boeing parts.

These preliminary inquiries eventually resulted in a request from George Bolt's son and Chief of Defence Staff at the time, Air Marshal Sir Richard Bolt, to conduct an official investigation.

NZ Army trucks on North Head Maungauika

1980 — First formal military investigation

The first formal military investigation into hidden tunnels under North Head / Maungauika was conducted by the NZ Army. It was a cursory search over three days from 18-21 March 1980. A few records were pulled, some interviews held, and a brief physical examination of the Torpedo Yard was carried out.


Despite some interesting reports and witnesses popping up, the drilling of eight exploratory holes uncovered nothing. Major G.D. Stevenson reported that he was of the opinion that there were no undiscovered tunnels or hidden aircraft on North Head—but couldn't give 100% assurance.

NZ Army bore holes 

1984-1988 — John Earnshaw & NZ Army

As a local North Shore resident and filmmaker, John Earnshaw was uniquely placed to undertake his own private investigation into the secrets under North Head / Maungauika. From 1984 he began interviewing witnesses and digging up evidence regarding the potential locations of hidden tunnels. What Earnshaw found was enough to convince the authorities another investigation was warranted.

With the support of the NZ Navy and Ministry of Works, 20 bore holes were drilled into locations of interest and ground radar was also used. The results of these tests, combined with eyewitness accounts and photographic evidence, convinced Earnshaw that a more in-depth investigation was required. So he formally applied to the Government for a license to investigate further.

Earnshaw's license was granted, with a number of conditions—summarised below:

  • The Crown agreed to assist John Earnshaw (and his company Mallard Productions Limited) in locating, excavating, and entering hidden tunnels under North Head.
  • John Earnshaw would claim ownership of any property found, which could be sold to the Crown for half the current market value.
  • The NZ Army would conduct the search due to fear of degrading ammunition. The investigation would be supervised by the Hauraki Gulf Maritime Park Board and the Historic Places Trust.

NZ Army drilling holes into floor


In Tunnel Vision, Martin Butler presents the diary entries recorded during the 10-day investigation of 1988. The comedy of errors that plays out over these seven pages alone is worth the price of the book. The author describes the result of the investigation as 'total shambles'.

Some highlights:

  • It takes three days for an Army machine to arrive and they show up with an old bulldozer with a faulty gearbox and no excavation buckets.
  • Army lacks any equipment to properly inspect or extract samples from the bore holes. Exploratory holes are peered into with a pentorch by 2nd Lt. Maindonald.
  • Army are uncooperative with Earnshaw for the duration of the investigation—refusing to investigate sites of interest, excluding him from meetings, and failing to provide equipment.

NZ Army erect barbed wire on North Head Maungauika

1992-94 — David Veart & Department of Conservation

In 1990, DoC became custodians of Maungauika (full ownership would not transfer until 2000). Due to public pressure and dissatisfaction surrounding the 1988 Army investigation, DoC commissioned their own investigation. Their goal was to prove "once and for all" what remained under North Head.

The Department funded a comprehensive investigation that was initiated in 1992.

NZ Army Navy and John Earnshaw


The investigation report was published in 1998 and concluded,

‘...that all the available evidence leads to only one conclusion: that there are no tunnels, no aeroplanes and no ammunition hidden at North Head’.

Veart, D (1998) North Head Tunnels Investigation Report Auckland Conservancy Historic Resource Series No. 15. Department of Conservation.

Tunnel Vision pokes a number of holes into the investigation, but the key points are:

  • The investigation relied heavily on incomplete archival research.
  • They did not excavate the sites where subsequent ground radar testing has determined that sealed tunnels exist.
  • They did not resolve the issue of toxic and explosive gasses found to be still emanating from the summit gun pit.
  • They did not satisfactorily investigate the site of the 1855 photograph showing a tunnel entrance (below).

1885 photograph of tunnel at north head / maungauika

1996-2001 — Court Cases: John Earnshaw vs Crown

Unsatisfied by Veart's investigation, John Earnshaw took his fight to the court room. There were two separate cases over a five-year period. Very brief summaries are below, more detail can be found in Tunnel Vision.


Case 1 - Crown found in breach of contract. Army failed to investigate in accordance with Earnshaw's License Agreement.

Case 2 - Judge Elias rules, based heavily on DoC investigation findings (or lack thereof), that there are no hidden tunnels and therefore, ammunition cannot exist within them. Discounts eye-witness evidence as “tricks of memory, lapses of memory, or contamination of memory".

graffiti death to you north head maungauika

2010-present — Martin Butler 'Tunnel Vision' investigation

Martin Butler continues to investigate North Head / Maungauika to this day. His book Tunnel Vision (Third Edition) showcases his research and the evidence he has found so far. He also continues to remind DoC to complete their mandatory gas testing every year; they seem to forget otherwise.


Ground-penetrating radar results from the 'Tunnel Vision' investigation has proven there to be sealed tunnels under North Head / Maungauika. No physical excavations have been permitted.

Back to blog

Leave a comment

Please note, comments need to be approved before they are published.