Hundreds of people, including about 300 family members of quake victims, have turned out to remember their lost loved ones at a service in Christchurch's Latimer Square.
Wednesday marks the first anniversary of the devastating magnitude 6.3 quake on February 22 last year which claimed 185 lives.
The Latimer Square service is focused on the quake victims' families, ahead of a civic memorial service at Hagley Park from midday.
The families are joined by Governor-General Sir Jerry Mateparae, Prime Minister John Key, Christchurch Mayor Bob Parker, MPs and ambassadors.
A number of the first emergency services staff to respond to the quake are also attending.
"This is a heavy day - heavy with emotion, heavy with loss, heavy with memories, heavy with sights that we were never prepared to see," Mr Parker told those gathered in Latimer Square.
He thanked international and domestic rescue staff who rushed to Christchurch after the quake.
Latimer Square was transformed into a triage medical centre in the hours that followed the quake.
Christchurch will come to a standstill at 12:51pm - the time the quake struck a year ago - with two minutes of silence.
Following the service, family members will be taken by bus to ChristChurch Cathedral and the now-vacant sites of the Canterbury TV building, where 115 people died, and the Pyne Gould Corporation building, where a further 18 people died.
NZN