Staff at a hospital's A&E department received a rather unusual late-night patient - a koala.

The marsupial casually strolled through the automatic doors of Hamilton Base Hospital in Australia's Victoria state.

Surprised staff, not wanting to put any pressure on the animal, watched from a distance as it wandered around the emergency department's waiting room for about three minutes before showing itself back out.

The koala's visit was captured by security cameras.

"He was quite relaxed, just sort of checking everything out, and then he sort of came back past the doors and they opened and he went on out again," said health authority spokeswoman Brigid Kelly.

"He wasn't stressed at all. It was nice to just watch him poke around there for a little while."