Lindisfarne College rector Ken MacLeod told Hawke's Bay Today the school's staff, students and old boys were "deeply saddened to hear of the tragic loss [of Mr Duncan]".
"Hamish was a fine young man who was well-liked by staff and his peers. He was a kind, respectful young man who was sincere, honourable and genuine."
The rector said the young man, who had started training as a medic within the NZ Army since leaving school, was involved in a range of activities during his school years. He had a passion for speech and drama, gaining his ATCL qualification in public speaking.
His sporting interests included tennis, orienteering and canoe polo. He was acknowledged on a number of occasions within the school for academic excellence and achieved well in NCEA.
"Totally trustworthy, Hamish was a person who demonstrated humility and graciousness. He was always loyal and supportive of his friends, house and the college."
Mr Duncan was also giving of his time - offering to volunteer in the school library for two years.
"Service to others is a quality that we respected in Hamish and he volunteered to work in the college library for the final two years of his time at school.
"This is a sad time for our wider community and our thoughts and prayers go out to his family and friends."