Fire in the Sky
The flare-like object was first spotted by a fisherman near Whyalla.
Times reporter Aaron Leaman saw the object and thought it was a meteor.
A loud boom heard throughout the region was most likely to be from a meteorite, up to the size of a medicine ball, Stardome Observatory in Auckland says.
The loud boom was heard over Canterbury, with sightings as far afield as Hanmer Springs in North Canterbury, and Hinds in Mid-Canterbury.
Observatory spokesman Andrew Buckingham told NZPA: "We're still finding out what's going on".
Initial reports had come through the police communications system, with follow ups from eyewitness accounts.
"It sounds like a large meteor coming down... soccer ball size upwards," Mr Buckingham said.

A police dashboard camera caught a fireball streaking through the night over central Texas Tuesday night.
"It was the most spectacular thing I've ever seen - I have never seen anything like it before," he said. LaHooe called after he read my June 10 column in the Herald about the fireball that streaked across the sky June 2.
"It shot across the sky and looked like it landed right behind the Tetons," he said.
Resident astronomer Scott Young said the museum has received at least 100 calls about an eerie green light that appeared in the sky on Friday night. Young believes the object was either a small asteroid or a chunk of comet that shattered into several pieces after burning up in the Earth's atmosphere.
"The receptionist is doing nothing but answering calls and taking numbers right now and I think I'm up to 180 e-mails," he said. "Lots of people saw it."
"Anyone who saw it should count themselves as lucky -- they are probably not going to see another one like that in their lifetime," Scott Young said.
Each year, about 500 meteors reach the earth, but only five or six of these actually reach the hands of scientists for scientific studies.