A Brisbane hospital can perform a blood transfusion on a young Jehovah's Witness boy despite his parents objecting on religious grounds, a Queensland judge has ruled.

The seven-year-old was referred to the Brisbane facility from a regional hospital in 2008 over a case of jaundice, before his significant liver disease was uncovered.

He will require a life-saving transplant in the next two or three years and has been placed on a waiting list, however such a procedure is likely to involve administering blood products.

The boy's parents objected to this on the basis that they believe blood is sacred and to agree to accept a blood transfusion would be to infringe a biblical injunction to abstain from blood referred to in the book of Acts.

"They are, however, obviously concerned about their son and for his health and are willing to agree to a liver transplant," Supreme Court Justice James Douglas said in a written judgment.

"They are anxious in that context to receive an assurance that every appropriate and reasonable blood conservation measure be used before the doctors resort to the administration of a blood transfusion."

Under Queensland's Transplant and Anatomy Act, medical staff can administer blood products without the parents' consent if they believe it would save a child's life.

"The overwhelming majority of paediatric liver transplant patients have required blood product support, and performing liver transplants without blood products is exceptional," Justice Douglas noted.

Therefore there was good reason for the issue to be resolved "before the procedure is anywhere near commencement", he said.

Justice Douglas ordered that the hospital and its staff be authorised to administer blood products to the boy "according to good medical practice".