Photo by James Allan.
Jake (yellow helmet) and Theo Riddle, pictured at the park, became internet sensations last summer - their dad Steve's video of them performing tricks on their BMX bikes has registered almost 1.4 million hits.
Sunday's jam, starting at 3pm, will also mark the opening of the redesigned learners' area, which has doubled in size.
The park, which features more than 50 jumps, is maintained by the Queenstown Mountain Bike Club in conjunction with contractor Nathan Greenwood.
