The scrap over the future of ChristChurch cathedral is heading to the High Court.
The Great Christchurch Building Trust, which is seeking to have the earthquake-damaged cathedral restored, says it will seek to have the court declare the Anglican Church cannot take the cathedral down because it would breach the Church Property Trust Act.
"Nowhere in the Act does it give them the authority to destroy or deconstruct the buildings," Trust co-chairman Jim Anderton told NZ Newswire.
Mr Anderton said the court move was a last resort after the church had dismissed an engineering report that said the cathedral could be restored.
They would seek a declaratory judgment on whether the church could take the cathedral down or not.
If the trust was proved right they hoped to sit down and discuss with the church what could be done to rebuild the cathedral.
The trust will file the papers with the court on Tuesday.
Church spokesman Gavin Holley said it was "extraordinarily disappointed" at the prospect of legal action.
The church had thought long and hard about the fate of the cathedral, before deciding in the interests of safety to deconsecrate it and partially take it down, he said.
The trust had come into the debate late in the piece, and while the church had stopped work on the cathedral to listen to them and taken their views on board, it wasn't convinced rebuilding would be safe, he said.
The church did not think a $100-million restoration was "faithful stewardship" for the financially struggling groups that used the cathedral.
Professional assessors had said a restoration, leaving a replica cathedral, was of debatable cultural heritage value, Mr Holley said.
Rather the a restoration, the church wanted a future cathedral that "supports mission and ministry, serves the community, is inspirational and speaks to the past but looks to the future", he said.