Mr Exelby said he found the gathering cathartic, a feeling shared by others he spoke to.
"I didn't see a lot of emotional displays, but it was obvious that some people are still struggling with the passing of the boys. That's okay; people have to deal with that in their own time.
"But many people said that coming together like this - the communal singing, being together, eating together - it is all part of the healing of the heart experience."
Mr Exelby said the 40-minute service included a lot of beautiful, harmonious singing and hymnals.
In his speech, Aongatete Coolstores managing director Allan Dawson highlighted Fisiinaua Vaipulu and Tei Vaipulu, who came to Aongatete to take the places of their brother Koli and father Sitiveni.
"He spoke of the year that's been and how well the boys, who have come to take the places of their fallen brother and father, had fitted in," Mr Exelby said.
There was also prayer and a benediction from Brendan Gibbs, firefighter and local Anglican minister.
Several local firefighters, including some who responded that terrible night, attended the memorial and were thanked for their service.
After the memorial service, there was an enormous meal put on by the local Tongan community and the packhouse.
"There was suckling pig, oysters, mussels ... it was really brilliant," Mr Exelby said.
Relatives of Samuela Taukatelata performed a song they wrote in his memory called Samuela's Song. His wife and children were present at the memorial.
Mr Exelby said it was a "bitterly cold" afternoon, but the good hearty singing warmed the room.
