A bizarre wailing sound echoing around a huge Halifax construction site is confounding, and unsettling, those who hear it.

“It sounds like I imagine what a really loud ghost would sound like,” said one Halifax pedestrian.

Others say it’s more like a loud, clanging organ.

It sounds like a “banshee,” said a construction worker at the Nova Centre, a million-square-foot development that will include a financial centre, convention centre, hotel, residences and retail and entertainment.

“It’s like that woman she’s just yelling at you. She’s right scary and stuff.”

The mystery sound is heard in nearby bars and hotel rooms and some say it can be heard three or four blocks away from the construction site. Residents have pleaded with local officials on Twitter to make the noise stop.

People living and working in the area say the howling only happens when wind is blowing from the south. One engineer compared the cause of the sound to blowing over the top of a bottle.

"There could be some architectural feature or structural feature right now that has a cavity like a Coke bottle and as the wind blows over it, it would make that whistling sound. We’ve seen that before with other buildings," said Michael Wesolowsky of Swallow Acoustic Consultants in Mississauga.

The mystery may be solved soon. Construction officials believe the howling is caused by winds blowing across the unfinished roof.

With files from CTV Atlantic's Matt Woodman