Fungi scientist Pam O'Sullivan urges people against foraging and eating wild mushrooms in the Hunter.
"People should be very wary about that," Mrs O'Sullivan said.
"I can show people photos to say 'yes this is an edible fungus', but unless people really know their fungi it's so easy to mix them up with non-edible ones.
"Also you can have a perfectly edible mushroom, but if it's growing on a toxic substrate it's pulling the toxins in."
She gave the example of people foraging mushrooms in areas where chemicals may have been sprayed.
The deaths of three people from suspected poisoning with death cap mushrooms, after a Saturday lunch in small-town Victoria, has put a spotlight on fungi for a fortnight.
At least one online mushroom website lists death cap mushrooms as existing in the Hunter.
But Mrs O'Sullivan, a mycologist, said she did not know if they had been identified in the region.
"They tend to grow under exotic trees," she said.
They have been confused with "straw mushrooms", causing deaths in the ACT.
An ACT government fact sheet on the death cap mushroom [Amanita phalloides] states it is found across south-eastern Australia. It is responsible for 90 per cent of all deaths related to mushroom consumption.
Its cap is 40mm to 160mm wide and may be white, but is usually pale green to yellow in colour or fawn if the mushroom is older.
It is commonly found near established oak trees, usually during late summer to early winter after rain.
Professor Geoff Isbister - a poisons expert and clinician researcher at the University of Newcastle - said "we've never had a severe mushroom poisoning in the Hunter".
He said there had been cases of wild mushrooms causing gastrointestinal symptoms.
"After the rain in Newcastle, you'll see mushrooms growing virtually anywhere. Most of them are gastrointestinal toxins that can cause vomiting and diarrhoea," Professor Isbister said.
"You could be quite sick if you picked a lot of them and used them, but we rarely see that."
He said this could be because the Hunter doesn't have a big community of mushroom foragers.
"There's a certain amount of foraging for magic mushrooms, but we don't see a lot of that," he said.
Mrs O'Sullivan, co-author of A guide to common fungi of the Hunter-Central Rivers region, said mushrooms were "extremely important".
"There are so many good things about mushrooms," she said.
She said mushrooms were "critical for decomposition of dead matter and recycling nutrients into the soil and for plants".
"The more we learn about fungi, the more we realise how this intriguing kingdom of organisms underpins all life on Earth."
She said mushrooms were used to make bread, cheese, beer and wine, along with antibiotics and other drugs.
They were also used in "bioremediation", like cleaning up toxic chemicals, oil spills and nuclear waste.
She said mushroom producers do a great job and it was "rubbish" to think poisonous mushrooms could be bought from supermarkets.
"It's a very sad and serious situation down there [in Victoria]."
