An elderly man has been badly injured trying to break up a fight between his dog and a goanna in north Queensland.

Key points: The couple's Jack Russell cross was seriously injured in the attack

The couple's Jack Russell cross was seriously injured in the attack The man suffered significant blood loss, mainly from scratches

The man suffered significant blood loss, mainly from scratches The woman was bitten on the leg and treated for her injuries at Proserpine Hospital

The 72-year-old man underwent surgery after being bitten by the goanna while his wife was treated for her injuries at the Proserpine Hospital.

CQ Rescue said the man was flown to the Mackay Base Hospital overnight with significant leg and arm injuries after the incident at Flametree, near Airlie Beach on Thursday afternoon.

"The reptile suddenly turned on them, latching onto the man's right arm and leg as well as biting the woman's leg," a spokesman said.

"The man suffered a very serious laceration and possible fracture of his right forearm as well as severe bleeding from his leg wound. He was in considerable pain."

The rescue service described the attack as "a horrific and freak ordeal".

The couple's dog, a long-haired Jack Russell cross named Lily, was seriously injured.

Lily the dog (left) has survived the attack. ( Supplied )

It was earlier reported the dog had been killed, based on information received from the Queensland Ambulance Service.

The woman who was injured described Lily's survival as "the best news I've heard all day".

'The gentleman tried to save his dog'

Queensland Ambulance Service Senior Operations Supervisor Shane Tucker said the claws of the goanna would have caused damage.

"I would imagine it could have the potential for some significant, even life-threatening, injuries due to the nature of the animal," Mr Tucker said.

"Apparently the family dog went chasing this goanna and they got into an altercation and the gentlemen has tried to save his dog.

"His partner was also on the scene and was trying to separate the dog from the goanna as well, and she also sustained some minor injuries to her foot."

A goanna attacked an elderly couple in north Queensland. ( ABC News: Shelley Lloyd )

Mr Tucker said the man suffered significant blood loss, mainly from scratches.

"Due to the anatomy of a goanna, very sharp claws and I believe there were quite significant lacerations to his arms and his legs," he said.

"I believe they are quite an aggressive animal. Any wild animal that is cornered is going to protect itself.

"Definitely out of the ordinary. Sounds like he's quite lucky, however, to have sustained the injuries that he has and still be in a stable condition."

'They eat anything made of meat'

Lone Pine Koala Sanctuary reptile keeper Dave Ryan said goannas are lace monitors and could grow to almost 2 metres in length and weigh 3 to 4 kilograms.

"Unfortunately these lizards basically eat anything that's made out of meat, they're not fussy at all — so rodents, birds, they'll even eat other lizards, other reptiles, so something the size of a small dog or a cat is right up there on the menu for these guys," he said.

Lone Pine reptile keeper Dave Ryan says lace monitors have very sharp claws and teeth. ( ABC News )

"They have very sharp claws that they use for climbing trees and scratching open termite mounds ... but razor-sharp teeth.

"They will scratch your arms up, but the bite is far worse than any of the scratches, those razor-sharp teeth just open you up very, very easily.

"With habitat loss and building of more suburban areas a lot of these animals are getting pushed into smaller and smaller locations where they're competing more for food, food becomes scarce, so then they have to disperse back into those suburban areas."

Mr Ryan had one piece of advice for anyone encountering a goanna — "I would highly recommend leaving it alone".