Watch: Defending champion Braden Currie retires from Ironman NZ due to head cold

Defending champion Braden Currie has been forced to withdraw mid-race from this year's Ironman New Zealand due to a head cold.

Currie, who headlined a strong men's line-up competing in the Taupo event, has been battling a flu all week but was determined to not let it affect his chances of competing.

However, Currie pulled out of the race during the cycling leg after alread completing the swim section of the event.

The 31-year-old skipped this year's Coast to Coast race to prepare for the race which is in its 35th year.

12-time winner Cameron Brown remains in the race as a front contender.

The 45-year-old is up againts Terenzo Bozzone, who despite never winning the race in Taupo, has managed five podium finishes.

This year's race consists of a 3.8km swim, a 180km bike ride and a 42.2km run.

The defending champion pulled out during the cycling leg due to illness. Source: 1 NEWS