A teenager attacked by a crocodile after jumping into a north Queensland river on a dare from friends is lucky to still have his arm, paramedics say.

Key points: Teenager attacked by crocodile after jumping into Johnstone River in Innisfail in the early hours of the morning

Teenager attacked by crocodile after jumping into Johnstone River in Innisfail in the early hours of the morning Lee de Paauw is in Cairns Hospital in a stable condition

Lee de Paauw is in Cairns Hospital in a stable condition Paramedics say 18-year-old is lucky to still have his arm

Innisfail's Lee de Paauw was grabbed on the left arm by a crocodile as he was climbing out of the Johnstone River on Fitzgerald Esplanade about 2:30am on Saturday.

The 18-year-old managed to punch it with his right arm and escape.

Queensland Ambulance Service (QAS) officers called to the scene were initially told the teenager's hand had been amputated.

"He is very lucky. Initial reports was that his hand was completely amputated and on arrival that was not the case," QAS supervisor Rita Kelly said.

"So although he does have significant injuries, his arm is still intact, which is very fortunate."

Mr de Paauw was taken to Innisfail Hospital and later transferred to Cairns Hospital for further treatment.

He is in a stable condition.

QAS senior operations supervisor Neil Noble said the area was well-known for its crocodile population.

"Reports from the scene are that he was dared to jump into the water, which he did," Mr Noble said.

"We're just very grateful he survived because it could have turned out to be fatal."

Mr Noble said without quick medical attention it could have been a fatal attack.

"To get him out of the water was absolutely vital in case that crocodile was able to get a good grip, do a death roll and drown him, which I believe is often the case."