It's a crucial milestone in the fight to save the threatened species, as the devils settle in to their new home.

For Save the Tasmanian Devil Program director Howell Williams, it's a tremendous success.

``I guess you can hope for this, and actually seeing it is just great,'' Dr Williams said.

Fifteen devils were released on Maria Island in November last year as a key insurance population in the fight against the devil facial tumour disease.

``Bringing the devils to Maria Island was something we've talked about for a long time,'' Environment Minister Brian Wightman said.

``Our best chance of beating facial tumour disease is by establishing self-sustaining devil populations in safe havens like this.''

The Save the Tasmanian Devil Program aims to release another 35 devils in the next 18 months which, along with new-borns, could eventually take the total to 120.

Yesterday on Maria Island program workers checked the devil traps laid the previous evening.

Jimmy, Snips, Reba and Muffs were all checked and released back into the bush after getting the all-clear.

Reba's jelly bean-sized blob - a pouch-bound baby devil known as an imp - had Phil Wise, a wildlife biologist with the program, excited about the future of the species.

``We've got eight females on the island at the moment, and we've been able to catch five so far, and of all of those five, they've each got between two and four pouch young,'' Mr Wise said.

``It's very encouraging for us.''

Mr Wise was totally at ease handling the devils, which sat idly in a hessian bag in his lap as he and another program worker inspected their bodies - and teeth - without any fear.

Despite the Maria Island translocation success so far, Dr Williams wasn't getting carried away.

``The disease certainly is spreading through the devil population, and it's our assessment that the whole of the Tasmanian mainland will be affected by the disease in the next 10 to 15 years,'' he said.

``So this is a very important part of the conservation effort.  It'll be the major disease-free population of Tasmanian devils.''

Mr Wightman said the program was drawing much interest across Australia but also further abroad.

``This project is of international significance, there's no doubt about that,'' Mr Wightman said.

``Not just to save the Tasmanian devil but for the learnings that come out of this program for other animals all across the world.''

The fight against facial tumour disease is also being fought in laboratories as scientists struggle to understand and combat the cancer.

Scientists announced a breakthrough last month, with a critical discovery about how these cells behave that could eventually lead to a vaccine.

Dr Williams said they would continue to build on the Maria Island success, and would continue to look at other insurance populations to be held on Forestier, Tasman and Freycinet peninsulas.

Both Dr Williams and Mr Wightman said they were confident of maintaining federal funding for the program.