Mount Maunganui's Peter Campbell came second (1h 28m 32s) followed by Rotorua's Tony Broadhead in third (1h 29m 04s).
Meanwhile, in the women's race, 2010 and 2011 Rotorua Marathon winner Ottosson was too strong for the rest of the field, winning in 1h 33m 07s.
The local osteopath finished about seven minutes faster than Te Awamutu's Kirsten Milne (1h 40m 26s) in second and Rotorua's Sue Crowley (1h 40m 59s) in third.
Race director Murray Fleming, from Event Promotions, said the course had been changed this year to make it completely off-road in the forest.
He said they did not purposefully try and make it harder, but it did include some tough inclines this year.
He said a lot of the runners were using the half marathon as a build-up for the Rotorua Marathon in late April.
"It was first set up by Lake City Athletic Club and held on the roads around Ngongotaha," Fleming said. "And it was used as a pre-event to the Rotorua Marathon. But just with the sheer amount of traffic, and cost of traffic management, it was moved off-road."
Voss, who specialises as a 10km runner, said he was stoked to win the local event.
"It's always a good feeling to win and be out in front, and have the crowd cheering you on and the other club members," he said.
He said the course yesterday was pretty tough going.
"It was a pretty difficult course and quite hilly and quite tight on the single tracks, so it was definitely tougher than last year," he said.
Voss finished third during the 5km under-20s race at the New Zealand Track and Field Championships in Dunedin last week, but is still recovering from a knee injury.
