Animal welfare groups say 'time is of the essence' for wildlife injured in the Australia's devastating bushfires, as rescue teams on Kangaroo Island race against the clock to save the animals.

Devastating pictures have emerged of an injured koala that appears to be mourning the loss of its friend.

The photos, taken on Wednesday on South Australia’s Kangaroo Island, show the animal burying its face in its arms in sorrow, while its companion’s lifeless body lays nearby in a river.

A Humane Society International animal rescuer is then seen rushing over to pick up the injured koala and carry it to safety.

“There are some of the toughest scenes I’ve ever witnessed as an animal rescuer – the bodies of charred animals as far as the eye can see,” HSI’s senior specialist in disaster response Kelly Donithan told One Green Planet.

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She said every time they find an animal alive on the island, over a third of which was burned by a devastating fire on January 3, “it feels like a miracle”.

“As we set out each day on search and rescue, we’re still finding animals alive, injured, dazed or traumatised, and it’s such a relief to be able to give them immediate lifesaving assistance.”

Rescued koalas are being taken to a makeshift sanctuary at Kangaroo Island’s Wildlife Park.

An estimated 37,000 koalas have been killed, with Environment Minister Sussan Ley saying koalas in particular had taken an “extraordinary hit” and could be listed as endangered for the first time.

Experts on Kangaroo Island have predicted there were about 46,000 koalas on the island before the bushfires ravaged their natural habitat.

South Australia Veterinary Emergency Management leader Steven Selwood estimated just 9000 remain.

Mr Selwood said the figure was “pretty devastating”, adding that the fires were “particularly ferocious and fast-moving” meaning “a lot of the wildlife was incinerated”.

Despite incredible efforts from rescuers to save as many koalas as possible – including makeshift refuges in school halls – the continuing blazes and the destruction of their habitat have created the problem of where to send the animals once they’ve recovered.

Some of the animals were so badly injured they had to be euthanised.

The battle to save remaining wildlife creates a “rollercoaster of emotions”, HSI worker Evan Quartermain told AFP.

“Sometimes we’re out there for hours walking through catastrophic landscapes (with) hundreds and hundreds of bodies on the ground … and you get down,” Mr Quartermain said.

“You can’t help it – it’s extremely traumatic.”

Kangaroo Island is the only area in Australia where the koala population is free of chlamydia, which is fatal for the animals.

This means saving the animals on the island is crucial as they have long been seen as an “insurance population”.

Mr Quartermain said the experience has been “extremely traumatic”, “but then you find a (koala) joey at the end of the day and we bring it in and we give it a chance and we’re filled with joy”.

– With AFP