A PYTHON has been filmed crushing the life out of a wallaby in suburban Cairns.

Redlynch resident Demelza Canuto was driving home, when she came across the sight of a more than 3m long scrub python strangling a small wallaby along Cascades Drive, near Crystal Cascades, last Thursday.

Ms Canuto said the marsupial was beyond rescuing from the large reptile.

"We probably hung around for 15-20 minutes, just filming it," she said.

"Unfortunately that kind of spooked the python, and it untangled itself and slid off into the bush.

"We left it, and pulled the wallaby off the road.

"We had my daughter's graduation that night, and on the way home, we saw the python was back, and it had swallowed the wallaby."

She said the scene was both shocking and impressive.

"You don't expect to see something like that on the way home, even though we do live in a place where there's lots of bush around," she said.

"I was surprised at first, but it was very cool to watch."

Scrub pythons, also known as amethystine pythons, are the longest snake species in Australia, growing more than 8m long.

The rainforest-dwelling species are known as ambush predators, using constriction to kill its prey, which can include wallabies and even domestic pets.