The series attracts many of the top national championship contenders, and Clarke expects leading national enduro rider Chris Power, of Auckland, will make the journey.
Power won round one and will be keen to consolidate his position at the top.
Fellow Aucklander Mike Skinner pushed Power hard at round one and he will be looking to reverse the finish order this weekend.
Auckland's Sam Greenslade, Palmerston North's Adam Reeves and Hamilton's Sam Brown also rate among the favourites to win tomorrow.
As well as a two-hour race for the country's senior elite, two new classes have been added for the fifth annual Dirt Guide Cross Country Series, increasing the opportunity for the development of the country's younger riders.
The new classes are in motocross and trail bikes for children aged between six and 10 years and they will use a separate track from the juniors.
"These classes will race at the same time as the junior race and be 75 minutes duration," said Clarke.
"This is the fifth time I have run the series and each time it is getting bigger and bigger," said Clarke, a former International Six Days Enduro medal winner and multiple-time former national enduro champion.
He said there were classes to cater for all ages and abilities with the senior grade split into two sections, for intermediate and expert riders.
There are separate categories for women and veteran riders.
The junior race starts at 9.30am and the two-hour senior race starts at 12.30pm.
The cross country series is run parallel with but separate to the Dirt Guide Trail Ride Series, with that phase of the weekend's action set for the same venue the following day.
More than 120 senior riders lined up for the start of the Kiwi Rider-supported Dirt Guide series at round one and it looks like it will be a well-subscribed series once again this season.
Round three is at Whakamaru on June 30 and July 1.
