South Islanders have been treated to a rare sight, with a fireball lighting up the sky above at about 6:30pm.
However astronomer Alan Gilmore told Newshub it was not a meteor.
"The distinguishing point about it is that it was reported as moving fairly slowly and being seen for at least half a minute," Gilmore, a former superintendent at Canterbury University's Mt John Observatory, said.
"Your typical meteor would be seen for a second or two ... I've never seen a meteor that's taken more than five seconds to cross the sky."
A number of witnesses reported that the bright object was visible from anywhere between 25 seconds to two minutes.
Mr Gilmore said it's movement from west to east was also an indicator it was not a meteor, and likely to be shrapnel re-entering our atmosphere. An object traversing the sky in that direction indicates it was orbiting Earth, he says.
He said he only knows of one other occasion when an object re-entered the atmosphere above New Zealand, and he says he remembers that was also travelling west to east.
Dunedin resident Hayden Ferguson said he was just "outside having a beer in my backyard after work" when he saw "a big bright light".
"It was bigger than a plane - it was huge. I've never seen anything like it," he said.
Mr Ferguson said it lasted for "about two minutes" and "was sort of like a rainbow" in the way it traversed across the sky.
"I didn't have a clue what it was, I just thought, 'What the hell's that?" he said.
"It lit up the sky and I could see my whole lawn ... it was definitely something different. I didn't know what was going to happen next."
Waimate resident Andy Jacques described it as "absolutely stunning" in a post on weatherwatch.co.nz's Facebook page, and said it broke into four pieces as it travelled across the sky.
Mr Jacques said it was "the most incredible meteor" he had ever seen, and said it lasted somewhere between 25 and 30 seconds.
Facebook users Callum Law and Brian Gallagher witnessed the meteor and managed to get a video of it, which they posted on social media.
Weatherwatch said they had received "a couple dozen" reports from New Zealand of a meteor or fireball in the 30 minutes after it appeared. They say they usually receive 10 to 20 reports a day from sources around the world.