30/12/2016 1:10 PM AEDT | Updated 30/12/2016 1:13 PM AEDT

Potentially Deadly Irukandji Jellyfish Move South For The Summer

They're tiny, mysterious, and increasingly causing stings as far south as Fraser Island.

Romantic comedy 'Fools Gold' may not have been critically acclaimed or even particularly well received, but it should have become notorious to all Australians, as it served a deadly warning.

Production was halted not once but twice on the 2008 shoot for the Warner Bros film starring Matthew McConaughey and Kate Hudson because of thumbnail-sized jellyfish capable of inducing the deadly irukandji syndrome.

First, a crew member was stung in Cairns, where they have been known to live since the 60s. When production moved to the cooler southern waters of Fraser Island, where irukandji had not been known to live, safety officers checked the waters to see if any were present. They found so many, they cancelled the shoot for a second time.

We think there are at least eight species of jellyfish that give rise to the irukandji syndrome.Jamie Seymour

This was the first time irukandji jellyfish were found on Fraser island, and since then, expert Jamie Seymour said there had been about 10 sings on the island a year, including four people who were hospitalised just last week.

It's the latest in a summer of stings, Further north near Cairns, Ayllie White was stung in November despite wearing a stinger suit and some experts speculate the heart-attack deaths of two snorkelers within minutes of each other could also be irukandji.

Seymour, who is an associate professor at Australian institute of tropical health and medicine at James Cook University, was on the set of Fools Gold, and said that while the production company took the threat seriously, Australians generally don't understand the dangers of these mysterious, tiny jellyfish.

"To say that we have gaps in our knowledge is an understatement," Seymour told The Huffington Post Australia.

"We think there are at least eight species of jellyfish that give rise to the irukandji syndrome and we know the venom from each of them is different.

"When someone arrives at hospital with irujandki syndrome, we're reactive, we don't know what's going to happen to them.

"For some, they have a lot of pain, so they try to fix that, if their heart fails, they try to fix that, if they get pulmonary adema, or their blood pressure goes through the roof, they try to fix that, but they don't really know what's going to happen each time."

What is an irukandji jellyfish?

There is no one irukandji jellyfish, rather there are at least eight different species of jellyfish that cause a similar reaction when they sting people.

AFP/Getty Images
An irukandji jellyfish caught off the coast of Broome.

They can be found anywhere between the Tropic of Cancer and the Tropic of Capricorn and are mostly very small -- about the size of a fingernail.

They are named after the Indigenous Irukandji people, who knew of a sickness some people got after swimming at a certain time of year.

He said anyone who's been stung would not forget it any time soon, and he would know, because he's been stung 11 times.

"The pain is just surreal," he said.

"On a scale of zero to 10 with zero being no pain and 10 being extreme pain, I was at 13 or 14. The last time I was stung.

What we don't know about Irukandji jellyfish

How many species of jellyfish cause Irukandji syndrome

How a sting will affect someone and over what time period

How long the jellyfish live

Where they breed

How many offspring they have

The water temperature they can survive in

"For most people, the sting itself is mild. It feels like a sea lice bite. Then about 20 minutes later, everything goes wrong.

"The pain is the easy bit. For about 10 to 15 percent of people, their heart will fail and some of them will die."

The Nature of Science / YouTube
Jamie Seymour in hospital having been stung by an irukandji jellyfish.

Over the last decade, irukandji jellyfish have gradually caused stings further and further south, and Seymour said it was only a matter of time before they would be found on the Sunshine Coast.

"If we go back 10 or 15 years, people thought irukandji were only found around Cairns and Townsville area and the season was only about one month long.

"Since then, the season is about six months long and we can see from data of where people have been stung that they've moved much further south.

"When there are stings, the tourism industry often says it's an isolated incident, but it's not.

"These are cold-blooded species that are restricted by the water temperature. Their spread south correlates beautifully with increased warm ocean temperatures.

"It's like the East Australian Current from Finding Nemo -- they ride it down the coast of Australia, and when the water gets too cold, they die."

Seymour said now was the time to invest in understanding irukandji.

"When someone is stung on the Sunshine coast, their only option will be to close the beach, and that will go viral.

James Braund
There is yet to be a Sunshine Coast irukandji sting.

"All around the world, they'll hear about it, but if we knew more about their general biology, we'd be able to say, OK, they can survive in waters of 26 degrees, it's 25 degrees today so swimming is fine."

He said irukandji jellyfish should be given the same level of research as great white sharks.

"We've had half a dozen shark attacks in the last 12 months, with some deaths and the NSW Government threw millions of dollars towards research, which is great, it's what they should do. On average, we get 200 people in hospital due to Irukandji. Up north alone, we estimate this costs $10 million to $14 million a year to treat these people.

"We need to know where these things breed, where they live, really simple stuff because our knowledge right now is just not good enough."