"Sometimes when you're there doing it, it's your job and you're just doing it," he said.
"It's later when you stand back and reflect ... you realise what sort of effect it's had on you and your family. In speaking with a specialist, I found that lifted a weight off my shoulder."
Police unveiled a memorial plaque for the balloon accident at the annual pay parade in December, in appreciation of the hard work of officers, Mr Register said.
Carterton fire chief Wayne Robinson said some firefighters at the scene took up to six months to work through the personal impact of the tragedy.
"You always hear of these things happening around the world but you don't expect it at your doorstep," he said.
"It was certainly a once-in-a-lifetime event and some of our people took four, five, six months to sort through it all.
"It played on the minds of a couple of guys for months but we had the option of in-house counselling right from the start."
Mr Robinson said the Fire Service also held critical incident stress management meetings in the days and weeks after the tragedy for all staff who worked at the scene.
Mr Robinson said he, deputy chief Brian Styles and senior station officer Richard Epplett also talked with fellow firefighters, especially junior colleagues.
"Our newest member there had only been in for about 12 months - less than a year actually - so some had never even seen a fatal road crash let alone what they came across that morning.
"Speaking for myself, I tossed and turned that first night but I concentrated after that on helping the rest of the brigade and that focus on other members helped me as well."
Mr Robinson said another vivid memory was the camaraderie that developed between emergency workers at the scene of the balloon tragedy.
"There was a complete unity over those days."
