A severely disabled four-year-old boy taken from a Brisbane hospital has been found by police in northern NSW.

Queensland Police’s Detective Acting Inspector Grant Galston says the child is “OK” and on his way to a Newcastle hospital.

Insp Galston says his parents, who took the boy from Lady Cilento Children’s Hospital on Thursday, are co-operating with police.

His parents had previously said they believe his condition was caused by vaccines and feared hospital food would kill him.

Earlier this afternoon, the boy’s mother, Cini Walker, was spotted in Newcastle by a member of the public after Queensland Police made an appeal to find the wheelchair-bound child.

Insp Galston said the parents had custody of the boy, but doctors at Lady Cilento Children’s Hospital said he needed medical attention.

He said hospital staff were talking to the parents on Thursday but when they returned to the room a few minutes later, the couple had left with their son.

Ms Walker posted a video on Facebook on January 18 that stated her son would be taken by the Department of Child Safety if they did not take him to the hospital that night.

It was shared again on April 26.

Ms Walker questioned whether she even owned her son any more.

"How much more do we have to prove that we love our kid?" she said to the camera.

"He needs to get better and they're destroying that."

Ms Walker said the boy did not need or want to be back in hospital.

She believed medication would harm her son and hospital food would kill him because of his allergies.

"I hate watching my son being drugged up and he doesn't wake up because he's in a coma because of the medications they give him," she said.

"I've also told the doctors and the child services that I will not feed my son any of their stuff and I will fight for him not to have it.

"That will be the last thing he has because I believe he's allergic to it and he will seizure and he'll seizure to the point he'll die."