The freak phenomena happened not once, but twice, on Thursday and Friday afternoon about 6pm at Lajamanu, about 550km southwest of Katherine.

Christine Balmer, who took the photos of the fish on the ground and in a bucket, said she had to pinch herself when she was told "hundreds and hundreds" of small white fish had fallen from the sky.

"It rained fish in Lajamanu on Thursday and Friday night," she said,

"They fell from the sky everywhere.

"Locals were picking them up off the footy oval and on the ground everywhere.

"These fish were alive when they hit the ground."

Lajamanu sits on the edge of the Tanami Desert, hundreds of kilometres from Lake Argyle and Lake Elliott and even further from the coast. But it's not the first time the remote community has been bombarded by fins from above.

In 2004, locals reported fish falling from the sky, and in 1974, a similar incident captured international headlines.

The small white fish are believed to be spangled perch, which are very common through much of northern Australia.

Weather bureau senior forecaster Ashley Patterson said the geological conditions were perfect on Friday for a tornado in the Douglas Daly region.

He said it would have been an ideal weather situation to allow the phenomena to occur - but no tornados have been reported to the authority.

"It's a very unusual event," he said.

"With an updraft, (fish and water picked up) could get up high - up to 60,000 or 70,000 feet.

"Or possibly from a tornado over a large water body - but we haven't had any reports," he said.