WWII in Northland unearthed - and now in a podcast

Heritage New Zealand volunteer researchers Jack Kemp (Kerikeri) and Bill Guthrie (Oruru) make use of a vintage army jeep during their search for Northland World War II sites. Photo / Supplied

Northland's "secret war" features in a new podcast due to go live on Anzac Day on Monday.

The series, Aotearoa Unearthed, explores everything from toilets in colonial Christchurch to Māori rock art and Waikato's wetland pā.

One episode is devoted to "Fortress Northland", a little-known network of defences built in a panicked haste after the Japanese bombing of Pearl Harbour in December 1941.

Podcast editor Rosemary Baird, of Heritage New Zealand Pouhere Taonga, said rapid Japanese conquests in the Pacific prompted New Zealand's military and Public Works Department to fast-track plans to create a network of military camps, observation stations and other war infrastructure.

"Military leaders identified Northland as the most likely landing place for a Japanese invasion force, so huge resources were invested into developing military infrastructure that could meet this challenge," Baird said.

The sprawling network of camps and other facilities — including an integrated defence network in the Bay of Islands — disappeared in 1943 when the threat of invasion subsided, almost as quickly as it had appeared.

"It vanished almost literally overnight. Nobody knew much about it until Jack Kemp and Bill Guthrie, Heritage New Zealand volunteers in Northland, started investigating sites and interviewing people," she said.

Jack Kemp (left) and Bill Guthrie researched Northland locations connected to World War II. Photo / Supplied

"The podcast tells the story, in Jack and Bill's words, of the journey of discovery they embarked upon which has shed new light on this hitherto all but unknown aspect of Northland's war past."

Also interviewed for the podcast are Heritage New Zealand Northland staff Bill Edwards and James Robinson.

The episode, World War II in Northland, will be available on Spotify and iTunes from April 25. It's part 10 in the podcast series.

April 23-May 1 is also Archaeology Week 2022.