Police are investigating how a New South Wales teenager came to be bitten by an Inland Taipan, considered one of the world's most dangerous snakes.

The 17-year-old male from Kurri was bitten on the hand yesterday afternoon and is in a serious but stable condition in Newcastle's Mater hospital.

Wildlife rescue officials identified the snake, which is usually found in the Northern Territory and Queensland.

Police are concerned it may have been kept illegally but have ruled out any connection to the recent theft of snakes from a Hunter Valley zoo.

The teenager suffered a severe bite and police hope to speak to him about where the snake came from when he recovers.

Toxicologist at the Mater, Dr Geoff Isbister says recovering from such a bite can take weeks.

"It is probably one of our most dangerous snakes in Australia," he said

"It's a very large snake and when it bites, it definitely strikes, often strikes twice and envenoms in almost every case.

"In terms of its effects, it causes blood not to clot, but its most important effect is it causes neurotoxicity.

"So if it's not treated early, it can cause paralysis."

Dr Isbister says the teenager was lucky to have been treated quickly.

"We had anti-venom in stock, we keep what's called polyvalent anti-venom and that covers all of our snakes.

"We use that rather than having Taipan anti-venom, there's not that much difference between Taipan and polyvalent, so we had access to it immediately, and he was treated very early."

Reptile rescuers say they are keen to find out where the snake came from.

Judy Martin from the Hunter Valley is taking care of the snake until the National Parks and Wildlife Service gives her further instructions.

She says the reptile is about a metre long and more than two years old.

"They are a very placid snake, they rarely bite," she said.

"It does take a lot to aggravate them to bite. We've had him since last night and he's shown no aggression whatsoever.

"He's the most toxic land snake in the world and we'd like to know where he came from, who gave it to the young guy."