Testing has confirmed that the red seaweed washing up on Coromandel beaches is harmless.

Results of a sample sent to The National Institute of Water and Atmospheric Research for testing confirmed it is a native alga known as Spyridia filamentosa or Hairy Basket Weed.

Red seaweed, also known as Hairy Basket Weed, which washed up on Whangapoua beach on the Coromandel in February 2014. Photo: WRC

Waikato Regional Council's Coromandel zone manager Tonia Clarkson says today's confirmation should give the public greater peace of mind.

'The council will continue to keep a close eye on the amount of the red seaweed being washed up on beaches as it can be potentially smelly in large amounts,” says Tonia.

'Any smell may get worse as the seaweed starts to break down and we're keen to hear from anyone sighting large accumulations of it on beaches.

The Coromandel situation comes after significant amounts of red seaweed were washed up on Northland and other east coast beaches.

Over summer it's common for this type of seaweed to accumulate in large clumps, adds Tonia.

'They are normally found offshore and further north of the Waikato region but the recent strong winds experienced have brought them Coromandel's way.”

Red seaweed also washed up last summer on the Coromandel but just at Whangapoua. This summer there have been reports of it at New Chums, Rings Beach, Matarangi and Cooks Beach.

To report sightings call the Waikato Regional Council's freephone on 0800-800-401.