Police have found a baby koala in a bag after arresting a 50-year-old woman in Brisbane.

Officers from the Upper Mount Gravatt Tactical Crime Squad stopped the woman, who was wanted on outstanding matters, on Newnham Road about 9:00 pm Sunday.

When asked if she had anything to declare before she was taken to the watch house, the woman handed over a green canvas bag and said it contained a koala.

When the disbelieving officer unzipped the bag, the baby marsupial emerged.

Senior Constable Rio Law with the baby koala found in the bag

The woman told police she found the koala on nearby Kessels Road at Nathan, and was caring for it.

Police are still investigating the claim and the woman has not been charged for any offence in relation to the joey.

The koala was picked up from the Brisbane City watch house by the RSPCA Ambulance.

RSPCA spokesman, Michael Beatty, said it was about six-months-old and in good health despite being a little dehydrated.

“He’s been on fluids but is doing well and will shortly be going out to a carer,” Mr Beatty said.

“He weighs 1.5 kg and we’ve called him Alfred.”

Mr Beatty said anyone who finds a koala should not to attempt to handle it.

The koala was a little dehydrated by otherwise in good health.

“Please call our animal emergency hotline on 1300 ANIMAL,” he said.

“Often the animal may have no obvious signs of injury but it can have internal injuries that need immediate attention.”