Confused Australians took to social media, and one even called police, after spotting the Wanaka released NASA balloon in the sky above Victoria and thinking it was a UFO.

Victorian Storm Chasers updated their Facebook page on Saturday with a post saying "We have had a few images coming into the page about the mysterious slow high flying light over parts of Victoria tonight.

"We are able to confirm that it is a Nasa Super Pressure Balloon (SPB) which was launched last month in New Zealand.



"The SPB is at an altitude of 33.5 km and the plan is that it stays afloat for 100 days."

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Facebook Confused Australians took to social media, and one even called police, after spotting the Wanaka released NASA balloon in the sky above Victoria and thinking it was a UFO.

Many people had commented on the post saying they had thought it was a UFO - or unidentified flying object - and the post had laid an unanswered question about what the mystery object was to rest.

Other's said they thought it was the planet Venus, a jellyfish in the sky or the Goodyear blimp.

The post was shared over 700 times and received almost 1000 comments.

9News.com.au reported that one witness was driving along the Hume Freeway between Benalla and Euroa when she saw the light in the sky.

"We were driving along and this guy was pointing and waving to us, and pointing to the sky. I thought, 'what's he doing?'" she said.

"I looked up and there was this weird thing in the sky, and there was a lot of other cars stopped to look at it too.

"It looked like a white circle with lines across it. It just didn't look right."

She said she called the police who took a report of the incident.

The $1.6 million helium balloon was launched from Wanaka Airport on March 27.

It was expected to circle the world two or three times before landing in South America.