IT'S commonly known as cornflake weed and it makes a splash in the ocean seem more like a swim in a giant bowl of breaky cereal.

Marine biologist and Hastings Point-based educator Ted Brambleby, of the Marine Environments Field Study Resource Centre, said the weed, which is washing up on shores and colouring the waters off our beaches brown, mostly came from the outer reefs.

"They call it cornflake weed and it's fairly regular weed that comes to our coastline...," Mr Brambleby said.

"I've seen it before. Summer often brings it in on the north-easterly winds. It spawns in summer and breaks up.

"The spores are on the inside of the bubble, so it opens and breaks up and eventually forms those fragments you see on the beaches."

One local resident said the problem was the worst she had seen in the 12 years she's lived on the Tweed.

Mr Brambleby, whose museum is within Northstar Holiday Resort Hastings Point, said the arrival of the weed was part of a natural process.

Technically named colpomenia sinuosa, the weed grows on other algae and reefs.

"It actually breeds on reefs and rocky shores, and we've got the big reef outside of Hastings Point, and the algae itself is related to a bubble weed. It grows on kelp-type plants and other weeds but the main thing is it's not going to hurt you and the fish don't like it because it gets in their gills, so it won't attract fish.

"Small crustaceans will have a go on it... and they did say years ago leather-jackets (fish) might have a go at it. But nothing much feeds on it."

Some people believe the weed also brings sea lice, something the local marine expert denied. He said there was no such thing as sea lice and what was commonly thought to be lice was actually something else.

"It's small crustaceans, about 1mm in size, like tiny little shrimp, very tiny, they're not easy to see but can cause itchiness," he said.

"Broken up tentacles of certain jellyfish can also cause (itchiness)." And he said these sometimes get caught in weed.