The red seaweed which has shown up on the Coromandel shoreline in recent weeks is now being closely monitored by the Waikato Regional Council.

The seaweed is suspected to be a red alga known as Spyridia filamentosa or Hairy Basket Weed, which is native to New Zealand but also occurs across much of the world.

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

Coromandel zone manager Tonia Clarkson says testing will shortly confirm whether this is correct.

'While this is a completely natural event, masses of this non-toxic seaweed being washed up can cause an unpleasant odour,” says Tonia. 'Any smell is likely to get worse as the seaweed starts to break down.

'We're hoping nature will deal with it but, because of the odour risks, it is important to monitor it and we're keen to hear from people spotting large accumulations of it on their local beach.”

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

Tonia says over summer it's actually common for this type of seaweed to accumulate in large clumps.

Those clumps are normally found offshore and further north of the Waikato region but the recent strong winds courtesy of El Nino have bought them Coromandel's way, adds Tonia.

'Something similar happened last year on the Coromandel when we had close to El Nino weather but the red seaweed washing up was confined to Whangapoua. Now we've had reports of it at New Chums, Rings Beach, Matarangi and Cooks Beach.

'We've got staff out checking where else it might be and we're keen to hear from anybody who's spotted it at their local beach.”

To report any sightings of the red seweed washing up on the Coromandel shoreline call the Waikato Regional Council's freephone on 0800-800-401.