Creasy (31), a PhD student at the University of Otago, dominated all disciplines and won the event in 4hr 1min 4sec.
He was six minutes in front of Diederik Scheltinga with Dunedin's Chris Keogh third in 4hr 10min 58sec.
Creasy was first out of the water in the 2km swim in a time of 22min 32sec and his time was 2min 24sec faster than Keogh who had the second fastest time in the swim.
Creasy was 38sec faster than Scheltinga on the 90km cycling leg with his time of 2hr 17min 43sec and also ran 2min 6sec faster than Scheltinga on the 21km run with his time of 1hr 19min 44sec.
The win continued the remarkable year Creasy has had in ironman and triathlon events.
He won the world long distance triathlon in Spain in July in the age 30 to 34 grade and was first home in his age group at the world triathlon championships in Auckland last month.
Creasy naturally won his 30 to 39 age category at Lake Hood while Keogh was runner-up to Scheltinga in the 20 to 29 age grade.
Dunedin's Glen McSkimming finished sixth overall in 4hr 23min 46sec and was first in the 40 to 49 age group.
Dunedin sports masseur Geoff Williamson was seventh in 4hr 24min 6sec.
Dunedin's Tamsyn Hayes finished tenth in 4hr 27min 4sec and was the first woman home.
Her swim time was 26min 13sec, cycle leg 2hr 25min 40sec and run 1hr 33min 29sec.
