Last year at Inglewood Donaldson (33) became the oldest runner to win the title when he claimed his fifth national 100m title.
His first was in 1997 and he also won in 1999, 2000, 2007 (first equal with James Dolphin) and 2008.
Donaldson is one of three athletes who have won five New Zealand senior men's 100yd or 100m titles.
The others are George Smith (Auckland) 1898-1904, and Gus Nketia (Auckland) 1991-96. The most titles were won by 1956 Olympian Morrie Rae (Auckland), who won six between 1954 and 1959.
Ambler (19) burst on the national scene this summer by setting a New Zealand men's 19 record of 10.35sec when he beat Donaldson in Christchurch earlier this month.
The other contenders are Craig Bearda (Auckland), James Mortimer (Auckland) and Oluseyi Smith (Canada), who has a seeding time of 10.47sec.
Donaldson is a member of the New Zealand bobsleigh team which was attempting to qualify for next year's Winter Olympics and has only had two 100m races this year.
He ran 10.66sec at Christchurch and 10.74sec at the Australian championships at Brisbane last weekend.
He will be going into the event under-done but remains confident.
"I would never race if I didn't think I had a chance," Donaldson said. "I always like a new challenge."
The work with the bobsleigh team has given Donaldson more power at the start and he is unstoppable over the first 30m.
A record team of 53 athletes will represent Otago at Wellington.
Cory Innes, who has won the 400m title for the past three years, will face strong opposition from his Otago team-mate and training partner, Andrew Moore.
Innes set the Otago record of 46.57sec three years ago but has struggled to get close to this time since then.
Moore has switched from the shorter sprints to 400m this season and has a best time of 46.95sec.
Andrea Miller is certain to retain her 100m hurdles title and Gemma Radford is keen to retain her 400m hurdles title.
Other Other Otago medal contenders in the senior events are James List (800m), Marshall Hall (discus), Fiona and Nicola Hely (sprints), Jeram Huston (shot put), Todd Mansfield (sprints), Shireen Crumpton (5000m), Anna Smythe (sprints), Paul Whiting (1500m), Hannah Blair (javelin), and Louise Thayer (high jump).
