Frog Safe's Deborah Pergolotti has seen a lot of strange things in her 21 years as a frog carer, but until this week she had never seen a five-legged frog.

Key points: Conservation group Frog Safe say it is very rare to see a five-legged frog, however cane toads sometimes have extra legs

Conservation group Frog Safe say it is very rare to see a five-legged frog, however cane toads sometimes have extra legs The frog was transported to Cairns for amputation of the fifth leg to give it the best chance to thrive

The frog was transported to Cairns for amputation of the fifth leg to give it the best chance to thrive After two to three weeks' recovery time, the frog will be released back into the wild in Mackay

"[It is growing] right out of the front of the chest, it is like a Picasso painting, in miniature," Ms Pergolotti said.

"I have seen this in cane toads from south-east Queensland, but this is the first frog that has come in with this condition."

The amphibian was found in a Mackay backyard and was transported to a vet in Cairns to have the limb amputated.

The frog's additional limb was functional but due to its location it was thought the limb was hindering the amphibian's activities.

"Which is why we are pursuing the surgery option," Ms Pergolotti said.

"It has just got this third arm sticking out, it doesn't fold up properly like the other limbs do, so it is probably in the way of trying to catch enough food."

Due to the declining numbers of frogs, it was deemed worthwhile to amputate the amphibian's extra limb. ( Supplied: Frog Safe )

The common green tree frog is listed as Least Concern in the Queensland list of threatened species, however Ms Pergolotti said their numbers have been in decline for more than two decades, which is why they decided to proceed with the amputation.

"Every one of those saved frogs is a frog that might breed and continue the species," she said.

Frog leg amputations are not uncommon following injury, however Ms Pergolotti said the anaesthetic can take a toll on such a small animal.

The frog's surgery was completed on Thursday and it is being transported back to Frog Safe in Mission Beach where it will recover for two to three weeks before return to Mackay for release into the wild.