A tourist who had drunk 12 cans of beers before being attacked by a crocodile while swimming in a Queensland river fell asleep at his campsite before going to hospital for treatment.

Matt Martin was camping in an area of the northeastern state of Queensland known to be inhabited by crocodiles when he drank what he later described as half a slab - or 12 cans of beer.

When he dived into the river at Cow Bay in the topical far north of the state, he landed on a crocodile.

After a brief wrestling match with the reptile, Martin emerged with gashes on his face requiring 40 stitches, The Australian newspaper reported.

Admitting his face was "pretty messed up'' when he went back to his campsite, Mr Martin, 35, from Newcastle north of Sydney, then slept for seven hours before seeking medical help.

His injuries were so bad that when he finally did make it to hospital, he was holding a blanket to his face to stop the bleeding, the newspaper said.

Crocodiles inhabit most of the waterways in northern Australia and although attacks on humans are rare, they are potentially very dangerous and numbers have increased in recent years due to official protection after fears they might be wiped out by hunters.