A field of 52 rally cars will head off on Saturday, August 14 for a six-day challenge over the back roads from Mudgee to Young to raise vital funds to help kids and youth living with kidney disease.

"With the pandemic halting much of our community fundraising activity last year, it's great to have the Kidney Kar Rally back raising vital funds to help children and young people deal with the physical, emotional and psychological impacts of this life-changing disease," Kidney Health Australia chief executive officer Chris Forbes said.

Supercars driver Holdsworth said he is thrilled to be supporting the rally this year.

"It will be good fun being on the dirt tracks with some fellow car enthusiasts all while supporting a great cause," he said.

The itinerary will take the rally participants through Meadow Flat, Lithgow, Oberon, Cowra, West Wyalong, Hay, Finley and Narrandera before they finish in Young on Thursday, August 19.

This year's fundraising goal is $500,000 and the event director John Paine is confident the total will be raised.

The rally is not a race but a test of skills in which drivers have to navigate the off-road terrain.

However, the track is designed to allow the novice and the experienced to participate on a level playing field.

For more details about the Kidney Kar Rally or to donate to the teams taking part or the individual towns' fundraising pages, visit www.kidneykarrally.org.au