A minute's silence has been observed for the 185 people who were killed in the 2011 Canterbury earthquake, as hundreds gathered to mark the third anniversary of the tragedy.

It marked a "turning point'' for Christchurch, mayor Lianne Dalziel said during her speech at a memorial service held today at the Archery Lawn in the city's Botanic Gardens.

"We have been through a lot as a city and there is still much healing to be done,'' she said, adding that "sensitivity and empathy will help guide us through this fourth year''.

"Let us unite as we did after the earthquakes. For those of us who have been able to move on, let us reach out to those who are still struggling.


View a gallery of images from the memorial:

"For those who cannot move on, please do not be afraid to ask for our help... We can get through this together.''

Ms Dalziel said she had recently met with families of some of those who died during quake which devastated the city, who said they wanted lessons to be learned from the disaster.

"Their overriding message is that we honour the people lost in the earthquake by learning lessons from what happened and using the rebuild as an opportunity to make Christchurch a better place and an example of a truly safe city,'' she said.

"When someone dies in circumstances that might have been prevented, one of the only things that can create meaning from the loss is the knowledge that someone in the future has been saved from going through the pain of losing someone in such circumstances.

"It is the best way to honour those whose lives were lost.''

The legacy of the quake and its aftermath would be how the city had come together to "do something'' to help, she said, saying it was a "spirit we must encourage''.

"It is this sense of optimism and creativity that can be a legacy of our experience, making Christchurch not only a safe city but one which enables each one of us to create the life we want to lead,'' she said.


"Let us claim our future - remembering our past, honouring those whose lives were lost or changed forever, acknowledging the significance of Christchurch being the final resting place of many from overseas and what that means for their families, respecting all who make Christchurch their home and creating for ourselves a sense of place where we all belong.