The 130-year-old Anglican cathedral's huge stained glass Rose Window shattered in a 6.0-tremor that struck Monday, compounding damage from a 6.3-magnitude quake in February that killed 181 people and toppled its spire.

Bishop Victoria Williams said the cathedral, a symbol of the South Island city, was structurally compromised when its western wall toppled Monday and the entire building may need to be demolished.

"We know some of it will have to come down because of the damage, but whether we have to take the whole thing down is still a live question," she told the Christchurch Press.

The cathedral lies in the city centre "red zone", the worst-hit area during the quakes in February and this week, which remains off-limits to the public because the risk of falling masonry makes it too dangerous to enter.

The area has been rattled by three major earthquakes in nine months and there have been calls after the latest scare to move the whole downtown area to more stable land to the west of the existing central business district.

Christchurch's Anglican dean, Peter Beck, said if the city centre was shifted, the cathedral was likely to be rebuilt on a new site.

"We would like the cathedral to be in the city centre, where it always has been," he told The Press.

"If the city moves west, then the cathedral needs to be at the heart of the city. The cathedral...has been in the heart of our city almost from the beginning."

The 1905 Catholic Cathedral of the Blessed Sacrament was also facing demolition after arches supporting its surviving copper-clad dome were undermined in Monday's tremor, the building's management board said.

The dome was one of a pair that crowned the renaissance-style building before the other collapsed in February disaster.

"(The damage) would have to be described as severe, it's suffered another good shake," management board chairman Lance Ryan told Radio New Zealand.

He said engineers were assessing the building and it would be a month before its fate was known.

An 88-year-old man who fell over in his nursing home was the only fatality from Monday's 6.0 quake, which came about 80 minutes after another powerful jolt measuring 5.2.

Aftershocks of up to 3.8 continued Thursday but there were no reports of further damage.

Copyright APP (Associated Press of Pakistan), 2011

Copyright AFP (Agence France-Presse), 2011