The Rev Alan Webster conducted a service on the lawn outside the Christchurch South Library.
He told NZPA news service: "Quite a few churches around the city do not have clearance and people are nervous about being in an enclosed space anyway so we have decided to meet outside. This is an open space where people can relax together."
At Christchurch Cathedral, Bishop John Gray led a solemn service in memory of those who died when the cathedral's spire collapsed in the quake. It is feared more than twenty people were buried under the rubble.
People in the city have spoken of their strong desire to see the cathedral rebuilt.
Christchurch mayor Bob Parker was quoted by the New Zealand Herald as saying: "We can't let it go. It does deserve to be rebuilt, stone by stone.
"It is a symbol of all those that have gone before. We've lost a lot of things, but that is one we should not lose."
The 6.3-magnitude earthquake killed at least 147 people, with around 50 still missing.
Engineers inspecting the centre of Christchurch estimate that at least a third of the buildings will need to be razed.
A two-minute silence has been planned for Tuesday at 1251 local time (2351 GMT Monday) to mark a week since the quake struck.