The Ministry of Social Development's chief executive says the evil that took place in Ashburton's Work and Income office must not be forgotten.
Peggy Noble and Leigh Cleveland were shot dead on 1 September when a man entered the Ashburton office with a sawn-off shotgun. Their colleague, Lindy Curtis, was wounded.
Ministry chief executive Brendan Boyle told those gathered at a memorial service in the mid-Canterbury town that people will learn from the events, but must not forget the horror that happened.
"Every action that we take so that in the future staff will be safer will be a tribute to Leigh and Peggy, and all victims of this terrible act. But while we look for lessons we cannot ignore the darkness. We must not hesitate to condemn utterly the evil that occurred in the Ashburton office that day."
The office where the shootings took place would remain closed. Mr Boyle said a temporary facility would be set up shortly before a more long-term office is established, but not in the same building.
Mr Boyle said the women's deaths would not be in vain and steps have been taken to improve security at offices throughout New Zealand to prevent the same thing happening again.
Ashburton mayor Angus MacKay said the service was a chance to draw a line under the incident and that the disbelief that followed the shooting is starting to fade.
"The disbelief, I think, is over ... We would like to move on and be the caring society that we have been in the past."
Also at the memorial service were Prime Minister John Key, Labour leader David Cunliffe and Social Development Minister Paula Bennett and local MP Jo Goodhew.
The service had a strong religious element, with prayers led by a series of ministers from the Baptist and Presbyterian churches as well as the Salvation Army.
Tributes for women
Peggy Noble and Leigh Cleveland have been described as pillars of their community, and the incident has shaken Ashburton.
The main street was blocked off for the service, which included prayers and performances from Ashburton College's Kapa Haka group.
Among the crowd was Julie-Ann Wairepo, who paid tribute to Peggy Noble. She said Ms Noble helped her and her six children find a place to live when they first moved there.
Ms Wairepo said Ms Noble she pushed her in the right direction when she was looking for work and helped her son who could not read or write. She said Ms Noble helped hundreds of others just like her family and would be missed.
Leigh Cleveland was also remembered. Heather McCormack met Ms Cleveland 22 years ago through their shared love of dogs and said she had a heart of gold.
Ms McCormack said the large turnout to the service is testimony to the sort of town Ashburton is.
John Tully, 48, has been remanded in custody on two charges of murder and one of attempted murder over the incident. He will reappear on 23 September.