Doctors are warning of the serious, and even potentially deadly, risks the increasingly popular 'jelly' beads pose to a child's health.

Parents are being warned of the potentially deadly risks water or 'jelly' beads pose to children.

The water-absorbing beads are increasingly marketed as toys and learning aids for autistic children, sparking concern among poisons experts and doctors.

Made from super absorbent polymer, they can swell to 400 times their original size when immersed.

If swallowed by a child they could cause an obstruction of the gastrointestinal tract.

Dr Rose Cairns, a poisons specialist at the NSW Poisons Information Centre at Westmead Children's Hospital, says this could lead to serious complications and even death.

A six-month-old child overseas died after developing sepsis after surgery to remove a water bead obstructing the jejunum - is the second part of the small intestine.

A report published in the Medical Journal of Australia shows between 2004 and June 2016 there were 129 incidents involving children aged 0-14 and these beads reported to the NSW Poisons Centre (NSWPIC).

The majority of these cases, 87 per cent, occurred in the past three years since 2013.

While the Australian Competition and Consumer Commission has both urged companies not to market water beads as toys and alerted consumers to their risks, water beads continue to be sold as "fairy eggs", "jelly beads", and "hydro orbs" on toy shelves.

Dr Cairns and her co-authors say parents should know the risks associated with these products, and if their child swallows a water bead they should be assessed by a hospital doctor as soon as possible.

"Any patient who has ingested a water bead and has gastrointestinal symptoms should be assessed for potential obstruction," they wrote.