Former New Zealand under-23 champion Dodds, of Lake Hawea, wants to win badly in front of his home crowd after being pipped on the line at Wanaka for two second placings in the past two years.
He has thrown down the gauntlet and offered to double the winner's prize money of $2000 to anyone who can beat him tonight.
Palmerston North triathlete Gemmell has been based at the Pisa Range's Snow Farm altitude training facility during the past week and is coming down from the highlands to try to defeat Dodds.
Gemmell's appearance has been matched by defending Wanaka sprint race winner Martin van Barneveld, of Wellington, who returns to the course where he outsprinted Dodds to win last year.
Vidal's presence has also set tongues wagging about a possible race-day entry from his girlfriend, coaching charge and New Zealand Olympic triathlon representative Andrea Hewitt.
If Hewitt makes it to the start line, her appearance will add spice to a female race that looks like it is local favourite Nicky Samuels' to lose.
Samuels has had a busy lead-in to the Wanaka sprint tri, an event in which she was first two years ago and second in 2010.
She claimed sixth place in the New Zealand road cycling championships in Christchurch last week - before she hopped off the bike to set out on a half-hour training run - and is back in the water tomorrow morning to compete as a team swimmer in Challenge Wanaka.
Contact Tri Series organisers have been unable to confirm whether Warriner will defend her Wanaka sprint crown.
She returns as a finish-line announcer for Challenge Wanaka tomorrow - a role she carried out last year when she promised to come back and defend her sprint title.
Challenge Wanaka event director Victoria Murray-Orr said Warriner would compete in the sprint race, although triathlon pundits are doubtful, given the Olympian's early-season training schedule.
If Hewitt and Warriner fail to show, promising 19-year-old triathlete Maddie Brunton, of Te Awamutu, will be Samuels' main rival.
