There's been a spike in the number of people being poisoned by eating wild mushrooms in NSW, with authorities warning ingesting the fungi can be fatal.

Fourteen people presented at emergency departments suffering the symptoms of wild mushroom poisoning between April 29 and May 19, NSW Health said.

Nine cases occurred in the past week, with three people having to be admitted to hospital.

Between May 1 and May 18, the NSW Poisons Information Centre received 56 calls about mushroom exposure, with 37 cases related to foraging for mushrooms or mushrooms being ingested for recreational purposes.

Genevieve Adamo from the NSW Poisons Information Centre said constant moisture from the wet weather in NSW this year had extended the mushroom season.

"The dampness provides excellent growing conditions for wild mushrooms, but it is often difficult to recognise edible from poisonous mushrooms," Ms Adamo said.

"Mushrooms picked in the wild can make you very ill and could be lethal."

Cooking or boiling wild mushrooms does not make them safe to eat, with the Death Cap mushroom potentially causing fatal organ damage.

Some poisonous mushrooms look similar to edible wild mushrooms from Europe and Asia.

"There is no reliable way to identify mushrooms picked in the wild, so it's best to completely avoid picking or eating wild mushrooms. It is simply not worth the risk," Ms Adamo said.