Multiple premiership winning jockey Larry Cassidy is set to help New Zealand chase down the leaders on the second day of the State of Origin jockey series in Brisbane.

Cassidy, who will join Damian Browne riding for the kiwis, has the prime ride on favourite Mystic Opal in the second heat at Doomben on Saturday.

He has the advantage of having already won two races on the promising mare.

His other ride is on the handy Board Director in the first heat.

Cassidy left New Zealand 30 years ago and has since ridden 40 Group One winners as well as winning the Sydney and Brisbane jockeys' premierships.

He returned to riding in August after spending a year on the sidelines with knee problems and has ridden 28 winners in his comeback.

"The Origin series has been well received among the riders and its great to be part of it," Cassidy said.

Series sponsor UBET has New Zealand at $2.70 to win Saturday's round and at $5 to win overall behind NSW at $1.30.

NSW have a commanding lead after the first of the three days when Michael Rodd and Tim Clark dominated.

They aren't available for Saturday and Tegan Harrison and Tye Angland will wear the sky blue colours.