A 17-year-old Jehovah's Witness suffering from a lethal form of blood cancer and refusing treatment threatened to rip the IV needle out of his arm if doctors attempted a blood transfusion.

But the NSW Supreme Court has overruled the wishes of the patient, known only as ''X'', and his parents, ordering him to undergo the potentially lifesaving procedure.

Unusual case: The NSW Supreme Court is ordering a 17-year-old boy to undergo a blood transfusion. Credit:Domino Postiglione

The case is unusual because at the time of the court's ruling on March 28, X was just 10 months away from turning 18 - by which time he would be considered an adult and entitled to refuse blood products.

Usually, such court cases involve much younger children whose parents have refused to allow lifesaving treatment.