What's that flaming ball in the sky? Meteor seen from the Illawarra

They jumped on Facebook to check if anyone else had seen the big ball of light and were quickly met with similar reports.

David Finlay, a space rock enthusiast and administrator of Australian Meteor Reports, confirmed what people had witnessed was "a meteor, but a special kind of meteor we would call a fireball".

He said they happen more often than we realise.

"At some point over Australia, somebody will probably see something like that maybe a couple of times a week," Mr Finlay said.

"But the fact that it occurred over Sydney, millions of people get to see if it occurs over a heavily populated area."

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"It's a space rock and it hits the Earth's atmosphere and it's probably going at about 70,000 kilometers an hour," Mr Finlay said.

"When it hits the atmosphere, that causes a lot of friction, it heats up, the outside starts to vaporise and in the majority of cases they completely vaporise.

"But what people saw last night was it fragmenting and breaking up and some of it probably survived entering the atmosphere."

Mr Finlay believes the event happened off the east coast, around Sydney.

"We think this may have occurred over the ocean," he said.

"From some of the eyewitness reports, it's a little bit sketchy. People aren't that great with directions.

"Some are saying, 'Oh yeah, I saw it heading to the west' and other people are like, 'No, I was at the beach and I saw it heading to the east'.

"That's where the dash cam footage and any security camera footage can really help us."

In this case, Mr Finlay believes it was headed over the ocean.

"It's quite possible that some of it survived, but we don't think it would have landed on any ground at this stage," he said.

Mr Finlay said meteors that occur over the ocean and survive atmospheric entry are known as fish squishes by stargazers.

It was seen from all over the place.

"All over Sydney and I've heard from people as far west as Oberon, and there were ones I think down near Wagga," Mr Finlay said.

"I'm not too sure about to the north yet, but it was a fairly wide-ranging area."

No, it's just a small rock, Mr Finlay said.

"Space junk is what we classify as something that humans have put up in a space like a satellite or something like that," he said.

"So we know quite definitively that it's not space junk, just by the speed, space junk is much, much slower.

"This was was going quite quick but still relatively slow for a meteor."