Tasmanian Devils could soon be released into a mainland national park to compete with feral cats.

The Victorian Government is considering releasing the animals into the state's Wilsons Promontory National Park in an attempt to re-establish an ecological balance between feral cats, foxes and native wildlife.

Scientists say a bold management approach such as this is needed to save threatened species as a lack of large predators on the Australian mainland has allowed feral cats and foxes to decimate native wildlife populations and threatened species.

Feral cats have been in Australia for more than 100 years but mammalogist Professor Tim Flannery said their devastating impact on native wildlife has grown since recent pest management programs have decreased fox populations.

"As we have started to drive down fox populations by using bait... the next largest predator, the feral cat, has popped up because it [has taken] advantage of an ecological niche that has opened up for it," he said.

Reintroducing top predators into the food chain is seen as an emerging frontier in environmental management throughout the world.

The strategy was also explored by Professor Flannery in his book The Future Eaters, published in 1994.

"The reason I chose the Tasmanian devil and the Komodo dragon is that they are large Australian native predators that still survive on offshore islands... the thought was that [if reintroduced] they will start interacting with the mesocarnivores - the foxes and feral cats - and start perhaps having some impact," Professor Flannery said.

"The [Tasmanian] devil is a scavenger; it may take food from feral cats or foxes at certain times of the year that may limit their reproductive success, it may compete for nesting spaces and take their young."

Feral cats biggest threat facing Australian mammal populations

The Action Plan for Australian Mammals, released in June by the CSIRO, estimated there are 15 million feral cats in Australia and listed them as the number one threat to Australian mammals.

A feral cat in the Australian bush. ( www.taiko.org.nz )

The organisation also predicted 63 Australian species will become extinct unless action is taken.

Lead author of the plan, Professor John Woinarski, said Australia's current rate of extinction in is one or two mammals per decade.

"Over the next couple of decades we will probably lose another four to five species," he said.

"Eradication of cats is a dream until at least the next decade so we need to manipulate the landscape in a way that will reduce their predation pressure to a level where native animals can sustain that pressure."

Wilsons Promontory to be first testing ground

The bold strategy of introducing Tasmanian devils as predators could soon take place for the first time in Victoria's Wilsons Promontory National Park.

Victorian Minister for Environment and Climate Change Ryan Smith has told Radio National's Background Briefing program that a risk assessment has already been completed and a proposal is being prepared for the Government.

University of Tasmania's Professor Chris Johnson believes Tasmanian devils belong on the Australian mainland.

"Devils were widespread on the mainland until quite recently. They were extinct by the time the British arrived but it might not have been long before that there were plenty of devils in Victoria," he said.

Tidal River, Wilsons Promontory, Victoria. ( ABC: Carolyn Swann )

Professor Johnson said new research in Tasmania suggests that in areas where the devils have declined due to the facial tumour disease, feral cats have either increased in abundance or become more active.

"There has been some recent camera trap work that shows that the presence of devils makes it more likely that cats will not be present," he said.

"There are no extinctions of wildlife in Tasmania that we can blame on the feral cat but there are on mainland Australia.

"So we could create a better functioning ecosystem in places like Wilsons Prom by putting a large predator like the devil back into that system."

Federal Environment Minister Greg Hunt has announced a 10-year action plan to eradicate feral cat populations.

But when asked about the proposed Tasmanian devil release into Wilsons Promontory, Mr Hunt said he was not aware of the plans but was open to the idea.

"I would want to firstly see the support of the Victorian Government and the support of the relevant park authorities and associations," he said.

"Secondary, you would need to do an environmental impact statement to understand the implications and impacts."

Concern raised over unpredictable outcomes

University of Melbourne Associate Professor Michael McCarthy said while releasing Tasmanian devils onto the mainland has some potential, the ecological effects are unpredictable.

"There is still no conclusive scientific evidence that releasing top-order predators onto the mainland will suppress pest species," he said.

"Essentially the low densities of foxes in Tasmania mean that the whole predator dynamics are very different to what they are on the mainland."

"Devils are the same 'trophic level' as foxes; they are likely to reduce cat numbers and change cat behaviour but the interactions are still uncertain.

"Any program needs to be proceeded with caution and trials need to be carried out in contained areas using fenced reserves and the experiment needs to be replicated several times in different environments."

Professor Tim Flannery agrees that any devil release needs to be tested first.

"Let's fence an area with both cats and foxes and introduce a single-sex group of devils and study what happens because it's good science that is going to inform us," he said.

"While we do have a sense of what will happen, we still actually need to demonstrate that on the ground."

But Australian Wildlife Conservancy's chief scientist Sarah Legge, who is currently on the frontline of the mammal extinction wave, is calling for urgent action.

"We need to go down the radical road of releasing a disease and introducing Tasmanian devils. We have evidence that dingoes suppress the impacts of cats by changing their behaviour and density," she said.

"Baiting is not a silver bullet. There are some circumstances where you can use baits successfully, [such as] when cats are hungry, and you may be able to knock them down but other things also take bait and you might be knocking down dingoes.

"You are then taking out the top predator in the system which is two steps forward and two steps back."