"My blood sugar was low and my core temperature was at 34C," he said. The medical staff kept him at transition for 90 minutes while they treated him for hypothermia.
Remarkably, Lichtwark tried his best to finish the race but ran out of time, missing the cut-off time limit to continue.
He was stopped two laps (28km) into the run.
Lichtwark said he was disappointed but thanked the medical staff for picking up his hypothermia.
He said he was feeling drained yesterday but was recovering well.
Lichtwark has started six Ironman New Zealand races in the past, finishing four.
Meanwhile, fellow Rotorua athlete Ray Hewlett won the men's 65-69 age group race.
Hewlett completed the BDO Cycle Challenge earlier this month which set him up well for the 180km bike leg on Saturday.
"That helped with the bike, and the run was just the usual case of survival really. But I enjoyed the race and I was pleased to finish."
It was the tenth time Hewlett has completed the Ironman New Zealand race.
Rotorua's Nina Dobson also completed the race with a good time of 13hr 01min 27sec. She took part in the event after having endured brain surgery.
More than 20 people from Rotorua participated in the race.