Health authorities have issued an urgent warning about a surge in deadly mushrooms appearing in backyards and local parks as cooler autumn weather creates perfect growing conditions.

Mycologists say wild mushrooms are sprouting across parks and fields throughout the state, with poisonous death cap mushrooms often growing near oak trees and posing a fatal risk to humans and pets if consumed.

WATCH ABOVE: Experts warn that the cold weather may lead to a deadly fungus growing in Australian backyards

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The dangerous fungi are most common in Victoria, South Australia and Canberra where the soil is wet and crisp during the cooler months.

The Victorian Poisons Information Centre received more than 400 calls for help relating to mushroom exposure last year, with half of those calls coming from parents with children aged under five.

Mycologist Tom May with a potentially deadly mushroom Credit: 7NEWS

Experts say being able to identify dangerous mushrooms can be the difference between life and death.

“So this is a death cap mushroom and this is a really dangerous mushroom. It potentially can cause death if ingested,” Mycologist Tom May told 7NEWS.

“It has a number of specific characters. It’s usually yellow or greenish on the cap. It can be white or brown. It has this cup at the base of the stem. So it’s an important one to be aware of and definitely to avoid.”

Authorities stress there is no home test to check if mushrooms are safe, and the advice is clear: unless you’re an expert, don’t pick them up or consume them.