Two men have had a nervous 500-kilometre journey to Alice Springs after they saw one of Australia's deadliest snakes crawl into the engine of their car shortly before they headed off.

Alice Springs snake catcher Rex Neindorf said the men, who drove for 500km with a 1.4-metre-long, highly venomous snake in their car, were lucky to be alive.

Mr Neindorf, who runs the Alice Springs Reptile Centre, said the men had been surveying remote bush roads on the Plenty Highway hundreds of kilometres from Alice Springs and saw the big mulga snake (also commonly known as a king brown) crawl under their vehicle, but did not see it reappear.

"They'd seen it disappear under their vehicle, and looked around the other side and it didn't come out, so they'd knew it went into the car somewhere," Mr Neindorf said.

The men then drove back to Alice Springs and straight to Mr Neindorf's house to seek his help in removing the dangerous reptile.

'It could have got inside the cabin'

Mr Neindorf said the men were brave to have gone so far with the snake, which would have felt the vibrations from the drive and not settled during the journey.

Australia's most dangerous snakes: 1. Eastern brown snake 2. Western brown snake (also known as gwardar) 3. Mainland tiger snake 4. Inland taipan (also known as fierce snake) 5. Coastal taipan 6. Mulga snake (also known as king brown) 7. Lowlands copperhead 8. Small-eyed snake 9. Common death adder 10. Red-bellied black snake

"Once a snake has access to a vehicle, they can actually go almost anywhere," he said.

"This snake was quite large, so it was restricted in its movements, but it still could have got inside the actual cabin."

He said when he found the large snake, that was "as fat as someone's arm" had become wedged between the air filter and the front headlight.

"It was really wedged in," he said.

But after giving it a "bit of a jiggle" and a "friendly poke" he managed to extricate it.

Mulga snakes are commonly known as king browns and are listed as Australia's sixth most dangerous snake, as named by Australian Geographic.

They like to eat other snakes and can be found on hot summer nights in Central Australia along with another highly venomous species — the Western Brown.

Mr Neindorf said while it was not common for snakes to be found in cars, when they did get access to one, they could be tricky to find.

Snake in your car? Keep it running

Just last week Mr Neindorf pulled out a Stimson's Python that had popped its head out of the glove box of a family car.

"You could be sitting in your vehicle driving along and the snake's head will come out of the air conditioning vent right next to your arm on the steering wheel," Mr Neindorf said.

"The best thing to do if you think you might have a snake in your car, is leave the car running in the hot sun, so it overheats.

"Snakes can't tolerate too much heat, because they don't have sweat glands and so they will eventually crawl out of the vehicle."