Australian doctors have achieved the world's first pregnancy from ovarian tissue grown outside the pelvis.

Melbourne mother-to-be, Vali, 23, is now 25 weeks pregnant with twins, after having both of her ovaries removed when she was being treated for cancer.

Researchers at Melbourne IVF stored her ovarian tissue before she had cancer treatment, then seven years later grafted the tissue back to her abdominal wall.

Her own eggs successfully grew and were harvested from the tissue for IVF, then fertilised and placed back into her uterus.

It is the first time the procedure has been done anywhere in the world.

Researchers said gives hope to other cancer patients to conceive.

"We have proven that ovarian tissue can still work and function normally outside the pelvis which is its natural environment," said Associate Professor Kate Stern.

Vali said she is excited to be given the opportunity to have children. The twins are due in three months.

"I was really lucky with my doctor because he was really supportive and explained things and offered me opportunity to freeze tissue... (in the) hope that someday maybe in the future that something would be possible," she said.

Her partner Dean said he is amazed at the science behind the procedure.

"It sounds like science fiction to think someone could take something that was taken from Vali so many years ago and we could use it to get to this point now," he said.

"It's phenomenal. We never dreamt it would be possible."

The results were presented at the Fertility Society of Australia conference in Sydney.