The public is being warned to stay away from green algae found near Omokoroa while it is tested for toxicity.

Regional council scientists are working on identifying the blue-green algae that has bloomed near Omokoroa in Tauranga Harbour.

The public is being warned to stay away from green algae discovered near Omokoroa. Photo: BOPRC

It looks like fine, green cotton wool, and is growing amongst sea grass in an area of approximately 20 hectares in the upper reaches of Mangawhai Bay, on the eastern side of the Omokoroa Peninsula.

'It's a type of blue-green algae or cyanobacteria that looks a lot like a species called Lyngbya. We've seen it amongst sea grass beds in the harbour before but not on this scale,” says Regional Council Coastal Scientist Rob Win.

'We don't know at this stage if it's likely to be harmful to people or what's caused the bloom, so we suggest people avoid contact with it for now as a precautionary measure.”

It's likely to have occurred in response to unusually warm water temperatures in the harbour over summer and the high number of swans around Omokoroa, says Rob.

'There's lots of swan excrement in the water there at the moment that may have fuelled algae growth.”

The algae accumulates gas bubbles from high rates of photosynthesis around its filaments, causing algae clumps to rise to the surface and form large conspicuous floating mats.

'We're keeping an eye on it. In the meantime if anyone experiences irritation after contact with the algae, they should seek medical advice,” says Rob.