A woman has been left bloodied and required a four-day stay in hospital after being attacked by a koala north of Adelaide.

But despite her injuries, she says she doesn’t blame the animal for the brutal attack.

Williamstown woman Mary Anne Forster said she was walking her two dogs a fortnight ago when they pulled her towards a koala at the base of a tree.

“Obviously the koala felt very threatened because it attached itself with its mouth, jaws, to my leg and bit very hard, bit very deeply,” she said.

After a struggle, she managed to break free.

“Because it wouldn’t let go, I put my fingers in its mouth and pried its jaws open to release my leg,” Ms Forster said.

The assistant principal hobbled more than two kilometres home and was then taken to hospital.

View photos Ms Forster was taken to hospital after the koala bite. Photo: Supplied. More

She needed 12 stitches.

“All wild animals have dirty bites and so it was a matter of covering with the antibiotics because it became very infected, it was very swollen and painful,” she said.

Environmental experts have warned people to keep their distance if they spot a koala out in the wild.

“Just leave them alone, certainly don’t let dogs go near them because they will fight back, they’ve got big claws and big teeth,” Dr Deb Kelly from the Environment Department said.