Police are looking into the cause of what has been described as an “explosion” heard around Rotorua last night.

The loud bang was heard just before 10pm, with residents in western and southern suburbs of the city taking to social media to speculate on causes.

Glenn Smith captured the noise on a private security camera.

“You hear an explosion, then sounds like something raining down for a bit.”

Smith said there was no flash of light visible.

His video was taken from Fordlands looking towards Western Heights and Mt Ngongotahā.

One social media commenter said they thought it sounded like “shattering”, and said it set their dogs off in Glenholme.

Others described it as “a boom”, with the noise shaking windows.

Several commenters speculated the noise could have been caused by a drug lab explosion, while a gunshot, a car backfiring, fireworks or a transformer blowing up were other suggested potential causes.

A spokesperson said this morning that police were made aware of a loud noise in the Western Heights area following reports at about 10pm.

“Police attended and located nothing of note; however, it looks as though we will be making further enquiries where we can.”

Fire and Emergency NZ said they received one call but didn’t send anyone because there were no reports of fire.