For a stowaway who made a 16-kilometer (10-mile) journey squeezed in a wheel arch, a koala was lucky to escape with just scratches.

The driver of the four-wheel vehicle was unaware of the extra passenger until they arrived at their destination in the outskirts of Adelaide, Australia, and he heard some unusual cries.

After seeing the koala in the wheel arch, he immediately called animal rescuers, who removed the wheel and eventually extricated the frightened but very lucky animal.

"You think you've seen it all. No, I've never seen anything like that and it's absolutely incredible," said Fauna Rescue worker, Jane Brister.

The koala suffered superficial injuries and was covered in grease from under the car.

"She was crying a little bit, she was a little bit shaken, she was certainly in shock but I rushed her straight to the vet," Brister said.

The koala was dubbed Kelli, after one of the firefighters who rescued her.

"Kelli's one of our fine station officers and she led the rescue crew that day and she was quite excited to have such a good outcome," said Dave Juniper of the South Australian Metropolitan Fire Service.

After being cleaned up and monitored for a week, it was released back into the bush on Saturday.

"After everything she's been through, she's had so much stress and trauma, to see her just toddle off and up the tree, and currently she's found the biggest fork in the tree, she's snuggled up, she's fast asleep," Brister said.

Rescue workers say it's not unusual for koalas to seek shelter in unusual places.