Adelaide's southern beaches have been hit with an unusual deluge of seaweed pushed to shore by recent wild weather.

Seaweed is a common sight on the city's northern beaches during winter as the seagrass beds shed leaves.

But James Guy from the Department of Environment, Water and Natural Resources said strong winds had pushed mounds of seaweed to the shorelines of Glenelg, Brighton and Seacliff.

"The big swell and the strong north-westerlies have meant that seagrass rack has washed up onto the southern ends of our beaches," he said.

"The strong winds have also meant more than the usual amount of seagrass has washed up.

"It's a natural process, we need to just live with it and wind and waves will move it along the coast."

Authorities say it is unclear how long the seaweed will linger ( ABC News: Lauren Waldhuter )

He said it was impossible to predict how long the seaweed would linger.

"It may take days or it may take weeks or months to clear, or eventually it decomposes," he said.

"The strong south-westerly front on Sunday may shift the seagrass along the coast or it may bring more seagrass to the shore."

The Holdfast City Bay Council said it had no plans to try and clean up the mess and was happy to wait for nature to take its course.

It is illegal for councils or members of the public to remove seaweed from the beach.