Reports in the 'NZ Herald' tell of a mysterious humming sound of unknown origin, plaguing the lives of some of the people in the Auckland and the North shore area.

The symptoms are similar to those suffered by people with tinnitus, commonly associated with a prolonged high-frequency ringing in the ear.
One person described the noise as "low drone or rumble".

Scientists from Massey University, are visiting people who can hear the humming, and trying to measure the noise in the hope they will be able to identify its source.

A wife of one of the investigating scientists who could hear the noise, but her husband could not, said, " It was an awful noise and sensation".It feels creepy. It's not a place I'd like to live regularly,"

Author Rachel McAlpine based her 2005 novel 'The Humming' on her experiences of a mysterious humming in Puponga, near Farewell Spit.
The book featured an unknown humming noise that plagued only certain people in a small town.

Whatever could it be :question:

Interesting, Chris. Are there any theories associated with this story (or that you know of) as to what the humming is?

I investigated a bit further and came upon this topic:

The 'Taos Hum' is a low-pitched sound heard in numerous places worldwide, especially in the USA, UK, and northern europe. It is usually heard only in quiet environments, and is often described as sounding like a distant diesel engine. Since it has proven indetectable by microphones or VLF antennae, its source and nature is still a mystery.

The Hum is descibed most commonly as a deisel truck idling in the distance. Sometimes the sound is constant, sometime it constantly changes in loudness at between one and four times per second. Sometimes it has a slow "beat note" sound, other times a "morse code" effect. Some people perceive it as being louder
indoors than outside.

I include a link about this subject:

http://amasci.com/hum/hum.html

When I come to think of it some years ago,I also heard something similar to the noise of an engine, that seemed to be coming from far off.

It was a persistent buzz, with a definite pulse to it, which changed frequency now and again. This was only in the night when all was quiet. It sounded like it was coming from deep under the ground though.