"I've just had surgery for that on my stomach. So I tried to get back into training, then I needed time off again, so it is really cool to come to these events and [do well]," she said.
"I loved the course. A lot of half Ironman courses are quite flat, but I actually do a lot of my training on hills so I really enjoyed this course."
Hammond was behind for most of the race and caught second-placed Larisa Cochrane on the 21km run leg, winning by about five minutes.
Meanwhile, Graham O'Grady (New Plymouth) smashed the men's record finishing in a lightening fast time of 4h 7m 18s. It was about four minutes faster than the previous record, on the Rotorua course, set by O'Grady in 2010. O'Grady said he was happy to pull together a strong race after a disappointing fourth place at Ironman 70.3 Taupo a week earlier.
"Last weekend I felt a bit off," he said.
"It was a bit disappointing when you put a lot of effort into a race and don't get the result you want.
"So I thought I need to have a good run off the bike over a half marathon, and you can't do that in training. And my coach said why don't you do Rotorua.
"So this was a chance to come to a fun low key event for me and work on those little things, and hopefully it sets me up for the rest of the season."
O'Grady is one of the best athletes across the half Ironman distance in the country and said his next big race was the Port of Tauranga Half Ironman on January 9, which doubles as the New Zealand champs.
Second place went to Sam Clark (Ohope) who got close to O'Grady on the 90km bike but was unable to catch him on the 21km run.
"I was trying my best to catch him on the bike, as that's my forte now days. But I couldn't quite catch him and then he had a bit of a faster run than me.
"It is a case of always being on the back foot when you can't swim as fast as these guys but that will come."
Clark is primarily a multisport athlete and hopes to win the Coast to Coast in February, after finishing second at the big event earlier this year. He has only recently started to break into half Ironman races.
A record field of more than 700 participants took part in the half and quarter Ironman races.