A far north Queensland family saved a 22-month-old boy from the jaws of a four-metre-long scrub python after it latched onto the child while he was playing at the family home in Julatten, north of Cairns.

Mother Amanda Rutland said she was horrified when she discovered the snake had bitten her son and was wrapping its body around the young boy on the afternoon of October 13.

"Something that size and he's so tiny … It was scary as hell, I can't put into words," Ms Rutland said.

Naish and his three-year-old sister Evie-Blue, were playing on the back verandah when the python struck.

Ms Rutland said she was talking to her mum, and could see her two children in her peripheral vision, when she noticed her daughter's startled reaction.

"I've looked over and [Evie-Blue] is backing away from where Nash was and I thought 'That's a bit weird' and she jumped up on the table and the first thing that went through my head was 'snake'," she said.

Naish Dobson sits with his grandfather Ron Rutland and his mother Amanda a week after the attack. ( ABC News: Sharnie Kim )

Ms Rutland ran to her son's aid to find the snake biting his upper arm and starting to coil itself around him.

"The first thing I tried to do was put my hand in its mouth and try to [get it off] but it wasn't budging. Its head was nearly as big as my hand," Ms Rutland said.

She screamed out to her father Ronald for help and the pair tried to prise the snake off.

"He had the snake around his arm, biting him, so I dug my hands in to find his head and began squeezing it hard for 15 seconds and it didn't make any difference as the snake began wrapping itself around my arm," Mr Rutland said.

"I had to do something so I started stabbing him in the back with the knife down his spine. It took about four or five stabs before it realised what was going on and let go."

The boy's grandfather had to cut the snake's head off to get it to stop coiling around him. ( Supplied: Amanda Rutland )

Ms Rutland said she didn't want to kill the python, as she had seen it around the property before, but it was when the reptile turned on her father Ronald it was killed.

"There was just no way we could get him off, he was just pure muscle," she said.

Mr Rutland said he had to cut the snake's head off to get it to stop coiling around him.

Ronald Rutland said his grandson Naish has recovered well since the ordeal. ( Supplied: Amanda Rutland )

Paramedics were called to treat Naish who suffered two bites to his forearm and one on his upper arm.

He was taken to Mossman Hospital then Cairns Hospital for treatment.

Mr Rutland said the toddler has recovered well since the ordeal.

"It hasn't affected him at all except the marks on his arms, they'll go away no doubt."