Seasoned endurance campaigners Warren Good and Arron Black, of Dunedin, are the only pairing solely from the region.
Wanaka's Allan Dippie and Queenstown's Grant Aitken are both teaming up with Aucklanders.
Good's BMW E46 is running in the open category and he and Black's main rivals will be kart-turned-car-racing Auckland brothers Wade and Mitch Cunningham, driving a Porsche 997, and brothers Matt and Dwayne Carter, in their modified Australian V8 Supercar-style Ford Falcon.
The Cunningham 997 is one of five Porsche GT3 Cup Cars entered, with a second 997 in the hands of Andrew Bagnall and Ant Pedersen.
Dippie also competed in the recent Pukekohe race and was lying third after his driving partner Scott O'Donnell finished his three-hour stint.
Two laps into his drive, the Porsche's gearstick snapped in half and Dippie lost five laps while it was repaired, eventually finishing sixth overall.
Aitken and Grant Liston have a rallying background but are looking forward to reacquainting themselves with the endurance-style racing that they enjoyed earlier in their driving careers.
Aitken's Mitsubishi Evo 9 is in the production racing class and will run a standard fuel tank, meaning he and Liston will swap each hour, when they refuel.
Good and Black have a larger 120-litre tank and will only need to stop once, after two hours, while the Dippie-Maddren Porsche can run for about one hour 45 minutes before needing a splash and dash.
The Motorsport Company sponsorship manager Geoff Short said the event was originally meant to be run as two 500km races - one today and another tomorrow. However, entry numbers dictated running it with six classes, within a single race.
It will be the first New Zealand championship-awarded endurance event since the days of the two-event series Nissan Mobil 500 that was held on the Wellington street circuit and at Pukekohe Park Raceway.
