Treasurer Dominic Perrottet said the funding allocated in Tuesday's budget would provide better access to cutting-edge and lifesaving treatments, including CAR T-cell therapy.

"This funding offers real hope to the families of children suffering from rare and often fatal diseases by opening the door to new, innovative therapies," Mr Perrottet said.

"This is an exciting time in medicine. There is a wave of cell and gene therapies now available for rare, previously untreatable, often fatal conditions."

Health Minister Brad Hazzard said NSW had played a leading role in global research in the development of novel cell and gene therapies to treat rare, fatal conditions.

"This investment will help ensure NSW children with these rare and life-threatening conditions are given every chance possible at a longer, happier and healthier life."

The funding will give more access to CAR T-cell therapy which modifies a person's own immune cells to attack cancer, offering hope for remission and long-term survival for children and young adults with acute lymphoblastic leukaemia and adults with diffuse large B-cell lymphoma.

It will also provide potentially sight-saving gene therapy for children with the genetic blinding eye disease, retinitis pigmentosa.

Also available would be monoclonal antibody therapy for neuroblastoma, which vastly improves the outcomes for children with that type of cancer.

The funding would also provide gene-based therapies for spinal muscular atrophy, a fatal condition with few treatment options until recently.

Australian Associated Press