Neil Keene, The Daily Telegraph

IT'S not a bird, it's not a plane, and it's certainly not one of those errant weather balloons so often blamed for UFO sightings.

According to Sydney UFO investigator Doug Moffett, a bizarre shining orb filmed hovering near Batemans Bay on the south coast late last month is a genuine unidentified flying object.

Eurobodalla resident Ben Roberts filmed more than eight minutes of footage early on June 21 tracking the bright sphere of light flashing and moving above the horizon.

He said he was "amazed" by how bright the UFO appeared.

"It was not a plane," he said.

"There were no flashes and it was way too slow. Same for a helicopter - no flashes and too slow."

That doesn't necessarily mean it was a spacecraft full of alien lifeforms paying south coast residents an early morning visit.

But Mr Moffett, an investigator from UFO Research NSW, said it meant there was no reasonable explanation.

"It doesn't fit any of the usual suspects, such as Venus, planes, weather balloons or military flares," he said.

"I really don't see it being a remote controlled aircraft with LEDs because if someone was doing that they're probably not going to do it at night. It's what I would call a genuine UFO."

Mr Moffett said the planet Venus, which often shines brightly in the night sky, was often mistaken for a UFO because as its light penetrated the atmosphere it sometimes twinkled and appeared to move - a phenomenon known as scintillation.

However, the light captured on Mr Roberts' footage did not fit that scenario.

The south coast sighting is just one of dozens of UFOs reported above Australia every year.

Mr Moffett said another UFO, reportedly shaped like a half-dome with tentacle-like protrusions beneath, was spotted over the Central Coast last month.

Mr Moffett said the number of local sightings appeared to be on the rise.

"Certainly in world terms it has been a very busy year," he said.