Sun-seekers are being warned to watch out for jellyfish lurking in shallow waters off the coast of Dubai.

Swimmers have reported seeing scores of the critters in the shallow waters at Black Palace Beach in Umm Suqeim in recent days.

One woman reported spotting 40 of the gelatinous creatures, which have trailing tentacles that can sting unwitting swimmers, at the spot popular with families.

“I noticed parents trying to keep their kids out of the water,” she told 7Days. “A few children were shouting ‘monsters!’ at the jellyfish and pointing, while others were catching them in nets to bring onto the beach.”

The jellyfish spotted off Dubai are thought to be blue, a variety experts say are “not that dangerous”.

“The blue jellyfish are not that dangerous, and I’ve been swimming in them,” marine biologist Donna Meyrick told the newspaper. “But the red ones with the very thin tendrils in the water are the ones you should avoid.”

The majority of jellyfish stings are mild and don’t require medical treatment.

Applying shaving cream to the affected area can help to prevent the spread of toxins, and victims are advised to use a razor blade, credit card or shell to remove any nematocysts – small poisonous sacs – that may be stuck to the skin. Pain and swelling can be treated with painkillers.

If a jellyfish sting results in a severe reaction, such as breathing problems or chest pain, or if a sensitive part of the body such as the face has been stung, swimmers are advised to dial 999 immediately.