Gert Jordaan, founder of UFO Research of SA, said that between February 21 and February 27 many people reported seeing bright orange lights and flames in the sky.
He said that while some sightings could be attributed to meteor showers, others could have a more interesting explanation.
"Though meteors do glow orange, some of the sightings reported radical change in direction and speed. Some objects even remained stationary for five minutes or so. There might be some UFO phenomena occurring in areas around Cape Town," he told the Times newspaper.
Mr Jordaan said one other explanation was that there could be "some top-secret aircraft" being tested in the Western Cape.
"The second possibility is that life from another planet is surveying ours for making contact and offering knowledge."
Nicola Loaring, outreach astronomer for the South African Astronomical Observatory, told the newspaper that the most likely explanation for all the sightings were meteor showers, which are made up of small rocks that burn up as they enter the Earth's atmosphere.
"They are very common. They glow orange, sometimes green, can change colour, and usually end up white," she said.
She added that people might be more aware of such occurrences, especially since the recent repetition of end-of-the-world predictions.
"When they see a light they think the end of the world is coming," she was quoted as saying.
The report follows the launching of a rescue operation on Sunday February 24 in Port Alfred, in the Eastern Cape, after a "credible witness" reported seeing an aeroplane crash-landing into the sea close to the mouth of the Bihra River.
A statement released by South Africa's National Sea Rescue Institute said that police were alerted and a rescue boat launched after the report at 8pm.
It said that the Civil Aviation Authority, local and major airports around the country and the South African Air Force were alerted to investigate any signs of any aircraft overdue or missing, but none were reported.
"No reports of any aircraft overdue or missing are reported and there were no signs, by midnight, of any accident or crash landings or crash site of any aircraft or flying or falling objects in the area," the statement read.
"It remains unclear what the credible witness had seen – described as a sound like an aircraft and seeing an object plunge towards earth before disappearing out of sight but appearing to crash land and appearing to have resembled an aircraft."