Christchurch's iconic cathedral is coming down.

The building's fate has just been revealed by Bishop Victoria Matthews.

"The Cathedral will be deconstructed with the utmost care and respect while at the same time protecting the treasures within its walls," says Bishop Matthews.

She says there will be no bulldozers or wrecking balls as the church gets pulled down to two to three metres to sill level.

The building was badly damaged in the February 22, 2011, earthquake and has deteriorated since.

Today's decision follows months of controversy, with opposing factions unable to find a common ground.

The New Zealand Historic Places Trust says it is greatly disappointed to see Anglican Church leaders undertake the "most destructive" of options under discussion.

Chief executive Bruce Chapman says the decision will make it very difficult to "retain any sense of this very important building as it once was".

"Our consultant engineer remains confident that restoration or reconstruction in a strengthened form remains possible," says Mr Chapman.

He says the trust recognises their preferred option is a pricey one, but believes they would have been able to get local, national or international financial backing.