Auckland swimmers are being warned to take care as several beaches experience jellyfish blooms.

A jellyfish bloom is a sharp rise in numbers of the creatures within a short period of time.

Auckland Regional Public Health said warm water is attracting the jellyfish towards shore.

Their stings can cause some beachgoers to break out in a rash known as "sea-bather's eruption".

The health authority said children and those with allergies may get more severe reactions and become unwell for several days.

Bluebottle jellyfish - which produce a nasty sting - have also been spotted around the coast, with people being told to stay out of the water if these jellyfish are present.

By RNZ