The eight-year-old and his family are among three ambassadors for the St Giles event, which will raise funds for children's disability services.

Joseph has arthrogryposis, a condition that affects his joints and mobility.

"People should get behind this event because we are going to raise money and help kids like me," he said.

Joining Joseph in attempting to tackle the hill will be Tasmanian elite runner Kate Pedley, who joined cyclist Wes Sulzberger as the latest high- profile athlete to sign up for the Balfour Burn.

St Giles chief executive Ian Wright said having such high- profile athletes would immensely help their cause.

"Having athletes such as Kate and Wes certainly helps a lot as they are well known - and it will be really interesting to see them tested in something outside their comfort zone," he said.

Spirits are still high for organisers and participants despite the theft of a $400 banner promoting the event.

Mr Wright said the theft of the sign, which was on the corner of Charles and Balfour streets for two weeks and vanished on Tuesday, was frustrating.

The first ever Balfour Burn will be held on March 16 with 14 divisions to offer people many ways of feeling the burn.