The Ride to Recovery trek, which has attracted riders from around the country, was the brainchild of Tuturau farmer Johnny Perkins and is a tribute to his late wife Ava, who died of breast cancer.
He teamed up with Jenny Campbell, of Cromwell, and others to bring the 30km back-country trek to life.
The plan is to ride from Earnscleugh Station's woolshed, past Clyde, down through part of the Cromwell Gorge, up the hill, over Cairnmuir Station and through to Kawarau Station in Bannockburn.
Due to a slip that has closed Fruitgrowers Rd, and being unable to ride their horses across the alternative route of the Clyde Dam, the fundraisers will load their horses into floats and drive to the other side of the dam.
There will be a ribbon-cutting ceremony at near the Dunstan Arm Rowing Club about 8am before the riders, aged from 16 to 70-plus, leave.
By mid-afternoon, they should be at the Bannockburn inlet and by 5pm, they should be arriving at Kawarau Station.
Though injured and unable to ride, Mr Perkins will be joining a support crew.
Mrs Campbell said it would be the biggest trek other than Otago Goldfields Heritage Trust's cavalcade and she thought the high number of participants was due to the cause.
Each rider has paid a $150 fee and some have sought sponsorship, one woman alone raising $2000, which will go to the foundation.
Once the group reaches Kawarau Station this evening, there will be an auction of donated goods such as holiday packages.
Tomorrow, riders will take part in a four- to five-hour ride around Bannockburn's historic sites.
Mrs Campbell said it was hoped the event would return some time in the future and that it might even become a biennial ride.
