Wellington, Jan 4 (IANS): New Zealand beach-goers, especially in Auckland, have been warned of jellyfish stings, which are a common sight in the waters of the country during this time of the year.

It is common to start seeing more jellyfish at the beach at this time of year, The National Institute of Water and Atmospheric Research (NIWA) emeritus researcher and jellyfish expert Dennis Gordon said on Thursday.

"As soon as the days start to get longer and there's more daylight, you get a bloom of more plankton. When there is more plant plankton, there's more animal plankton, which means you get more shrimps and things, and jellyfish feed on those small crustaceans," Xinhua news agency quoted Gordon as saying.

Jellyfish stay near the surface as they follow food supplies.

Yet, with weak directional powers, many unlucky jellies find themselves gathered into dense groups and stranded on the beaches, he said.

Around 35 species of jellyfish are found in New Zealand waters, including the most frequently seen moon jellyfish, lion's mane and spotted jellyfish, he said.

"Despite being really beautiful, the lion's mane and spotted jellyfish can produce a very painful sting," Gordon said.

"If you see a jellyfish next to you in the water, the chances are you can out-swim it," he said, suggesting people wear a wetsuit if it is known that there may be jellyfish in the area.