• Strange lights have been sighted across WA's Midwest, from the coast to hundreds of kilometres inland, prompting widespread unidentified aerial phenomena speculation.
• The Mid West Ports Authority has suggested the lights could be caused by ship light refraction.
• But Perth Observatory says the sightings extend well beyond the ocean, with reports coming from far inland.

A string of sightings of strange lights in the sky has sparked community chatter across Western Australia's Midwest, with no clear explanation yet for the phenomena.

Father and son Shane and Bradley Plane were driving near Point Moore in Geraldton, 420 kilometres north of Perth, when they spotted three or four lights in the sky.

"We were driving towards the lighthouse and I said to Brad, 'See that star up there? It's not looking right,'" Mr Plane said.

Bradley Plane said the objects, which they spotted on September 10, appeared to be moving in various formations.

"It looked like they were in a triangle. The flashing of them, it was like a rainbow," he said.

Reports from across region

Perth Observatory said it had received multiple reports of lights across a widespread area around the same time and as far inland as the northern Goldfields.

Spokesperson Matt Woods said the spread and number of the sightings was unusual.

"We've had sightings as far east as Laverton, Mount Magnet and Cue, all the way back to the coast," he said.

"It's very confusing."

Mr Woods said he first checked flight radar for aircraft activity but found nothing.

"Is there something being tested? A company trialling drones, or something new being worked on? It will be very interesting to find out what it is," he said.

Matt Woods says Perth Observatory has received multiple reports of strange lights from across the Midwest. (ABC Midwest and Wheatbelt: Chris Lewis)

The Department of Defence has confirmed there were no military training activities in the area on the night of the sightings.

Lights of this kind are known variously as unidentified anomalous phenomena or unidentified aerial phenomena (UAP).

NASA defines the term as the observation of objects or events in the sky, or other domains such as the sea, that cannot be identified or are not known natural phenomena confirmed through scientific method.

Mid West Ports Authority harbour master Heathcliff Pimento believed the cause was atmospheric refraction — a known phenomenon that can make ship or fishing boat lights appear to hover, drift, or vanish.

Heathcliff Pimento says the lights are most likely the refraction of lights from ships. (ABC Midwest and Wheatbelt: Chris Lewis)

"Sometimes a colder mass of air is trapped beneath a warmer mass of air that creates a duct that bends light, making it appear as though an object is floating before suddenly disappearing," he said.

He said such mirages did not appear on radar.

"You'd see the lights but the object itself isn't actually there," he said.

Heathcliff Pimento says the lights are most likely the refraction of lights from ships. (ABC Midwest and Wheatbelt: Chris Lewis)

But Matt Woods is not convinced by the explanation.

"It would have to be a very large refraction for the whole Midwest to see it," he said.

"Possibly it could be, but it's interesting that it's been reported as far inland as Laverton.

"I'd be very interested to know what it is."

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