Tasmanian devils with tumours the size of golf balls have had their cancerous growths disappear, after scientists successfully trialled a new way to kick-start the animals' immune system.

"At the end of three months there was nothing there, just a bit of scar tissue" said Menzies Institute for Medical Research immunologist Greg Woods.

Something to shout about: scientists have found a way to shrink a cancer threatening Tasmanian devils. Credit:Joe Armao

The new approach works by alerting the animal's immune system to the presence of the deadly cancer, which is normally able to fly under the radar.

Known as devil facial tumour disease, the highly infectious cancer kills devils within three to five months of the facial tumours first appearing.