The Big Easy was set up as a mountain-bike race five years ago but organisers Terry Davis, of Cromwell, and Ed Stevens, of Wanaka - co-directors of Highland Events, added the marathon the following year.
Both events have grown steadily over the years, particularly the marathon, which has more than doubled its entries this year to around 80.
When Mr Stevens first began ferrying Big Easy runners to the start line on top of the Pisa Range four years ago, a mini-van was the mode of transport.
''Now it's two 40-seater buses.''
The 48km mountain-bike ride has attracted about 130 entries so far - similar to last year, although that event usually attracted a lot of last-minute registrations, so record numbers were possible there, too.
''People hang back wanting to see what the weather's doing.''
Competing in the highest mountain marathon or mountain-bike race in New Zealand was a big drawcard, as was the ''incredibly scenic'' course, Mr Stevens said.
The marathon, which attracts runners from as far away as Auckland, starts near Bob Lee Hut about 4km from the Snow Farm lodge.
It follows the mountain-bike route to the bottom of the hill below the airport before joining the Upper Clutha River Track - a new section of the course this year - along to the Albert Town Tavern.
Dunedin police officer Mel Aitken, who broke the women's record for the run by an 18-minute margin last year, will return to defend her title.
The Big Easy mountain-bike ride starts at the Snow Farm and climbs to near the summit of Mt Pisa before riders tackle a big downhill to Luggate, finishing with a cross-country section to Albert Town.
Wanaka multisport athlete Dougal Allan - fresh from finishing third in his first long-distance triathlon last weekend - will be among the top riders on the start line.
Easier 30km races are available for runners and riders, along with a 13km Clutha River Trail run and a family-friendly 18km Lil' Easy ride.
