Health authorities in Australia have warned people not to pick and eat a variety of mushrooms which grow near oak trees.

People in Australia have been poisoned and even killed by the Deathcap mushrooms, which resemble edible ones.

Mushroom expert Teresa Lebel from Victoria's Royal Botanical Gardens said on Thursday that Deathcaps were now growing across Australia, and always near oak trees.

Symptoms of poisoning can appear similar to those of a gastrointestinal upset, while some people may not present any symptoms at all for up to 12 hours, Teresa Lebel said.

But then the poison reactivates and can cause liver failure and death, local media reported.

"The Deathcap is extremely toxic, and responsible for 90 percent of all mushroom poisoning deaths. Death can follow within 48 hours," acting Victorian Chief Health Officer Michael Ackland said.