There’s a tunnel under Dunedin no one has entered in 40 years – until now

Beneath the streets of Dunedin’s historic city centre lies a forgotten piece of infrastructure — a sealed tunnel no one has entered since the early 1980s.

It’s never been part of a public tour. It doesn’t appear on tourist maps. And until recently, even council staff weren’t entirely sure where it ended.

Now, after four decades of silence, the tunnel has finally been reopened — and what’s inside is surprising even the experts.

A hidden legacy beneath the Octagon

The tunnel, originally constructed in the late 19th century, is believed to have been part of an early drainage, steam or transport network linked to Dunedin’s industrial boom.

Running beneath sections of Stuart Street and Princes Street, the structure was bricked off and abandoned in the early 1980s following major city upgrades.

Since then, it has remained untouched — until contractors, working on earthquake strengthening beneath a heritage building, uncovered a sealed access shaft in late April 2025.

“We didn’t even know it was there,” said one worker.

“The plans just showed a void. Then we hit brick.”

First steps into the unknown

A specialist team from the council’s heritage and infrastructure unit was called in. What they found was a perfectly preserved subterranean corridor, around 2 metres wide, lined with old brick and cast iron, and stretching more than 300 metres under the city.

Inside were remnants of early utility work: rusted pipes, soot-stained walls, and a series of iron access hatches — most bolted shut.

There were no signs of flooding or collapse. In fact, the air was remarkably dry.
But what caught the team off guard was what wasn’t in any archive.

“There are markings on the walls no one can explain,” says one archaeologist. “Symbols, dates, names. Some of them etched. Some burned in. And none of them match official records.”

Why was it sealed?

No clear answer has been given. While officials point to redundancy — the tunnel no longer serving a functional purpose — some historians believe the decision to brick it up may have had more to do with public safety.

Old newspaper clippings from the 1970s mention a series of mysterious tremors in central Dunedin, as well as rumours of “deep voids under the city” causing instability in old buildings.

Others recall local legends of “the burning room”, supposedly a chamber beneath the Octagon where coal or steam lines once exploded — though no documentation of such an event exists.

Will the public ever see it?

Not anytime soon. For now, the tunnel remains closed off again, pending structural and cultural assessments.

Council staff have confirmed that archaeologists and heritage experts are continuing to document the site, but there are no plans to turn it into an attraction.

However, a 3D scan of the tunnel is reportedly in development, and could be released to the public later this year.

A city with secrets

For a place known for its cathedrals, student life and Victorian facades, Dunedin has layers of history still hidden below the surface — sometimes literally.

And now, one of those layers has been reopened for the first time in a generation.

Because even in a city built on stories, some chapters have been buried deeper than most.