Feral cats in Australia are descended from animals that arrived after European settlement, confirming their devastating impact on local wildlife, researchers say.

Two separate studies analysed the genomes of feral cats from around Australia to determine whether Australian populations are related to Asian cats or came from European stock, and when they arrived.

Although most evidence suggests that cats arrived with early European settlers, it is possible that some animals came ashore from shipwrecks off Western Australia around 1600, arrived with Malaysian fishermen in northern Australia from about 1650, or even arrived with the dingo around 4,500 years ago.

A team led by Dr Katrin Koch from the Senkenberg Biodiversity and Climate Research Centre in Frankfurt compared the genomes of 266 feral cats from the Australian mainland and six of its islands to cats from European and south-east Asian populations.

They report in in BMC Evolutionary Biology that mitochondrial DNA ties most Australian populations to Europe, while those on islands close to Asia, such as Christmas Island, share more heritage with Asian cats.

Dr Peter Spencer from Murdoch University lead a team which analysed short tandem repeat (STR) genomic markers, which are prone to mutation, in 830 cats.

They report in the Journal of Heredity that most mainland cats stemmed from a few small populations which were probably introduced a few hundred years ago.

Both studies concluded that Australian cats originated in Europe and arrived in Australia in several small populations which spread rapidly.

"The genetic structure is consistent with a rapid westerly expansion from eastern Australia and a limited expansion in coastal Western Australia," Dr Spencer writes.

Dr Koch suggests that some cats may have been introduced from Asia after European settlement.

Dating helps confirm devastating impacts of introduced predators

Both research teams explain that identifying precisely when cats arrived in Australia is important in determining how big an impact cats, foxes, dingos and other predators have each had on Australian native wildlife.

"The continent has a complex and ancient faunal assemblage that is dominated by endemic rodents and marsupials and lacks the large placental carnivores found on other large continents," Dr Spender says.

"Cats are now ubiquitous across the entire Australian continent and have been implicit in the range contraction or extinction of its small to medium sized (<3.5kg) mammals."

Dr Koch notes that cats have prevented attempts to reintroduce threatened species in parts of Australia.

If cats were present in Australia before native populations started experiencing rapid declines, it is possible that they have been unfairly blamed. However, this research confirms that the introduction of cats does match up local extinctions.

In recent years, attempts to protect or reintroduce native species have included programs to eliminate local cat populations.

Tasmania's Bruny Island is close to becoming cat free, Tasman Island achieved that status in 2011, and cat containment laws and cat-proof fences have been established in mainland areas.

A plan by Environment Minister Greg Hunt to cull 2 million feral cats, which he described as "tsunamis of violence and death for Australia's native species," was attacked by actress Brigitte Bardot and animal rights groups.