"I have been doing some velodrome racing to get more explosive on the bike,'' he said of his new approach. "I really felt that on the bike leg today. You've got to have a point of difference - evolve and adapt like the Brownlees' approach to ITU racing. If you do the same thing every year you're not going to get any quicker and that was half the reason why I did this.''
Ellice was in a group of three, including Kemp and Docherty, which overhauled James Hodge, a Tasmanian 20-year-old, halfway through the run. Hodge had set the pace until that point with excellent swim and cycle legs.
Ellice, who was seventh after the 1.9km swim leg in the Viaduct Harbour, was the next one to drop off the pace with about 8km remaining, before Docherty, who had looked strong, also succumbed.
"I came here to win,'' Docherty said. "To be honest, I felt pretty average all day. The way I felt, second is a pretty good result.''
Docherty, who has retired from the ITU circuit, has impressed in the longer 70.3 races - his next outing will be to defend his title at Ironman 70.3 Panama - but maintains his focus is on his first full ironman, the New Zealand event in Taupo on March 2.
"It was quite tactical on the bike but I just tried to hide and conserve my energy. I felt okay on the run but I just didn't have that spring that would have won the race.
"I didn't crash and burn, I just didn't have that spring in my step.''
A victorious Kemp said: "If it was any longer, I don't think I would have got there. I was really stinging at the end and I'm sure Bevan was gaining on me.''
In the women's race, Australian Annabel Luxford led from start to finish to win in 4:19:18, a performance which included an eye-catching cycle leg. Her cycle split of 2:22:14 was more than three minutes faster than 10-time Ironman New Zealand champion Cameron Brown, although the Kiwi was using the race as training for the Taupo event.
Swiss Caroline Steffen was second, almost six minutes behind Luxford, with American Meredith Kessler third.
Ironman 70.3 Auckland results:
Men: Christian Kemp (AUS) 3:56:02, 1; Bevan Docherty (NZL) 3:56:36, 2; Clark Ellice (NZL) 3:58:23, 3; Paul Ambrose (GBR) 3:59:26, 4; James Hodge (AUS) 4:00:55, 5.
Women: Annabel Luxford (AUS) 4:19:18, 1; Caroline Steffen (SUI) 4:25:15, 2; Meredith Kessler (USA) 4:29:24, 3; Sarah Crowley (AUS) 4:32:04, 4; Anna Ross (NZL) 4:34:25, 5.