Mr Duffy's son Jack was born with cerebral palsy spastic quadriplegia and cannot walk or talk - but that has not stopped him from completing some of the toughest walking tracks in Tasmania.

Sitting in a specially-designed backpack, Mr Duffy has carried his son hundreds of kilometres and raised thousands of dollars for charity along the way.

The latest Overland Jack campaign is set to be different.

Yesterday, members of the Launceston Fire Brigade, of which Mr Duffy is a part, came together at the local bowls club to raise money for the family's chosen charity, Life Without Borders.

More than 25 firefighters joined in for some friendly competition to help their friend and colleague.

Mr Duffy said the entire fire service had been "absolutely fantastic" throughout the entire campaign.

"The fire service have got behind this without any asking on our behalf," Mr Duffy said.

"On the walk itself we've got four firefighters, one paramedic and two police coming along."

As the six-night walk gets closer, Mr Duffy said he managed to fit in some training at the weekend when he took Jack up the Walls of Jerusalem track in central Tasmania.

"Just under two months to go now and it's looking good," he said.

"Jack's not very expressive, but you can tell when he's happy and when he's sad and whenever I throw him on my back he gets pretty excited.

"All up with his pack he's about 37 kilograms, so there's a lot of extra weight to carry," he said.

For more information or to follow the Duffy journey visit the Overland Jack Duffy Facebook page here.