Noise control officers in the capital are trying to track down the source of a mysterious humming sound around Wellington's inner suburbs.
They're investigating complaints of a low-pitched droning noise in Mt Victoria, Mt Cook and Newtown.
Its source is a mystery, and it's causing sleepless nights.
"Most people have rung in the middle of the night and they have described it as a low-pitched hum that basically keeps them awake," says council spokesperson Clayton Anderson.
Mount Victoria resident and writer Marian Evans says she heard the hum on and off yesterday but hasn’t heard it today.
“I recognised the hum because it’s unlike anything else I’ve heard which I usually block out when I’m writing,” she says.
Other residents describe the hum as sounding similar to a hum recorded by scientists on Auckland's North Shore in 2006.
"My partner heard something that she thought was a hum on Sunday," one resident told 3 News.
Noise control officers despatched by the city council have failed to find the source, let alone hear the sound themselves.
One theory is that power stations create the noise, but this one is on the other side of town.
Another theory is it is houses in dips or hollows that hear the sound, and when the wind blows over the hill, it creates a resonance effect.
Some people think it's the cumulative effect of many fridges sitting next to sinks and reverberating.
And people aren't shy about coming forward with their own theories.
"One guy said it could be extractor fans from bakeries that work at night, that's like, yeah, but there's no bakeries really in Mount Vic," says Mr Anderson.
"Another guy said it could be Smaug, the dragon from The Hobbit, lying under Mount Vic."
It's perhaps another theory for the council to investigate.
3 News