Ongoing protests fail to halt works.
Work has begun to remove the remains of the Christ Church Cathedral tower.
Crews began to tentatively pull masonry from the tower at 11.40am local time. Masonry was pulled from the top of the west wall of the tower.
It is not known how long it will take to demolish the tower. Depending on the strength of the tower remains, it could take between two days and a week.
The upper part of the tower collapsed during the February 2011 quake and more was demolished last year to make it safe.
The north wall and the interior of its base were removed last year.
Pulling down the remains of the tower will allow workers to remove more stained-glass windows from the cathedral.
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