Kim and Gavin Fitt with their son Riley, 4,  and Paula and Andrew Moloney prepare for the big red kidney walk.

Kim and Gavin Fitt with their son Riley, 4, and Paula and Andrew Moloney prepare for the big red kidney walk. Photo: Jay Cronan

KIDNEY disease kills more than 14,000 Australians each year - more than breast cancer and prostate cancer combined - and it can creep up quietly.

Kim Fitt, of Queanbeyan, was one of many with the chronic disease who lost most kidney function before she had a diagnosed symptom.

The now mother of one was 27 when she had the first of her kidney transplants.

''I had reflux [regurgitation of stomach contents to the oesophagus] during my childhood years, just my parts weren't working properly - it was never diagnosed as a symptom [of kidney disease],'' Mrs Fitt said.

''By the time I had my first transplant, I was down to 10 per cent kidney health - I did get quite sick in the end.''

Her sister donated a kidney at that time and, in 2011, her husband, Gavin, sacrificed one of his - through a paired kidney exchange with another couple - to enable Mrs Fitt's second transplant. Mr Fitt said it was not a hard decision to donate.

''For me, it wasn't a question of whether I should or shouldn't - I wanted Reilly, our four-year-old boy, to have a mum and I wanted a wife,'' he said.

The Fitts will be taking part in Canberra's first Big Red Kidney Walk around Lake Burley Griffin on Sunday morning.

Paula Moloney has brought the walk to the nation's capital after her husband, Andrew, learnt he was one of the 1.3 million Australians who had undiagnosed kidney disease.

''I was shocked when my husband suffered a heart attack at 39, but even more shocked to find out that we are now facing a future of kidney dialysis and eventually a full transplant of both kidneys,'' Mrs Moloney said.

Mrs Moloney said she was hoping for at least 500 people to complete the walk and had set a fund-raising target of $5000 to go to Kidney Health Australia's research. Participants in the Big Red Kidney Walk can register near the Carillon at 9.30am on Sunday.