The normally beautiful beaches of Byron Bay, on the New South Wales north coast, are being smothered by a blanket of cornflake weed that just won't go away.

Key points: The cornflake weed (Colpomenia sinuosa) is not unusual for this time of year but normally dissipates much sooner

The cornflake weed (Colpomenia sinuosa) is not unusual for this time of year but normally dissipates much sooner The weed plays an important role in a healthy marine ecosystem

The weed plays an important role in a healthy marine ecosystem The weed can be used as compost or fertiliser, but cannot be taken from marine parks, to which Byron Bay belongs

The algae is a common sight on beaches in the region at this time of year, but weeks of relentless northerly winds have not given it a chance to dissipate.

Mark Anderson, from the local Stingrays Swimming Club, said he had never seen anything like it.

"The weed is quite unusual, we do see it sometimes but we've not seen it at such thickness and breadth along the coast," he said.

"It's really like a minestrone soup. It goes out for another 50 to 60 metres.

"I don't call it disgusting, it's just nature's way of being nature."

Not afraid of a bit of weed — Byron Bay ocean swimmer Savaad Wells. ( ABC North Coast: Bruce MacKenzie )

Fellow swimmer Savaad Wells braved today's murky conditions.

"Have you ever swum in porridge? It's a bit like that," he said.

"I had difficulty seeing may hands under the water, but I could see as far as my elbow.

"The flaky cornflake thing, it sort of hits your face like pins and needles.

"This is the worst I've seen it for a long, long time. Just as you think it's going, it just seems to all come back in again and get worse."

A beach blanket of rotting weed is not a good look for a place that relies on its natural beauty to attract about 2 million visitors a year.

But the Byron Shire Council's coastal coordinator, Chloe Dowsett, said there were no plans for a clean-up and there were no public safety or health implications.

"It's just not very nice, it's like swimming in your bowl of soggy cornflakes," she said.

Jasmin Sezer plays in the cornflake seaweed at a Byron Bay beach. ( Supplied: Michelle Pullen )

"We don't have a plan to remove it and I don't think we would be allowed to as it is a marine park and it's part of the natural process.

"I can't say it will be going away any time soon, hopefully I'm wrong. Sometimes it just gets taken away with the tide."

Ms Dowsett said the weed played an important role in a healthy marine ecosystem.

"The weed that gets over onto the beaches, it breaks down and becomes lots of food for all the critters like crabs … and all the tiny little creatures that actually live in sand."

There's clear water out there somewhere — local swimmers say the cornflake weed extends up to 60 metres out to sea. ( ABC North Coast: Bruce MacKenzie )

The New South Wales Department of Primary Industries advised the ABC cornflake weed (Colpomenia sinuosa) was a non-native species, but was not listed as either notifiable matter or prohibited matter, meaning there was no offence under the NSW Biosecurity Act 2015 for being in possession of it.

The weed can be used as compost or fertiliser, but a 20kg-a-day limit applies, and it cannot be taken from sanctuary zones of marine parks.

The DPI urged people to contact their local fisheries office before collecting cornflake weed for fertiliser, and to ensure it did not enter any other waterways, to minimise the risk of spread of aquatic pests and diseases.