Barnes will ride Jackfrost in today's opening race before the pair head to Waikato.
The pair will stay in Christchurch until Monday before floating to the North Island.
Today's race will be Jackfrost's last public hit-out before he races in the Great Northern Hurdles at Te Aroha on September 9.
Barnes has been charged by trainers Brian and Shane Anderton with travelling with the horse and preparing him for the $125,000 feature.
Jackfrost has thrived since his dominant win in the Grand National Hurdles at Riccarton earlier this month.
''He has done very well, his work has been good, and this flat run should top him off before he heads north,'' Brian Anderton said.
Buddy Lammas has been booked to ride the grey hurdler in the Great Northern Hurdles.
He will fill in for regular rider Stuart Higgins, who was suspended for his excessive whip use on Jackfrost in his Grand National victory.
It is not beyond the realms of possibility that Jackfrost will go a cheeky race in today's 2100m event.
His stablemate Satin Guru will give the grey a good run for his money, though. Satin Guru went a solid race for sixth in his last start at the Grand National Carnival.
Rival Spider Lily beat him home and is 0.5kg better off in the handicaps than Satin Guru than in their last meeting.
Another rival, Lin, was comprehensively beaten by both horses in the same race. Before that run, she won a similar race to today's contest at Ashburton.
