There's another call from overseas to look at conserving Christchurch Cathedral.

The UNESCO World Heritage Centre says while the cathedral isn't a world heritage site, its symbolic value needs to be taken into account.

Spokesperson Gina Doubleday says while the survival of the cathedral might appear to be expensive at first, saving would help maintain the character of the city, bring it business opportunities and increase property values in the long term.

Ms Doubleday says a restored cathedral would testify to history and continuity of cultural life that a brand new building wouldn't be able to convey.