Canterbury's new catholic bishop is reconsidering restoration of the earthquake-damaged Cathedral of the Blessed Sacrament.

Paul Martin, who was ordained as the new bishop in March, is exploring other options, including building a new catholic cathedral on a more central Christchurch site. He plans to ask architects to draw up concepts for what a new cathedral might look like on a $40m budget.

Martin cast doubt on the $105 million restoration budget. The catholic diocese has a $30 million insurance payout for the Barbadoes St cathedral, but would need to raise any funds beyond that.

Joseph Johnson/Stuff New Catholic Bishop Paul Martin walking past the hoardings around the damaged cathedral.

"If we got it for $105m it would be a miracle," Martin said.

"Most of these things don't cost less than you think ... they usually cost more."

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DAVID HALLETT/STUFF The cathedral at dusk in 2002.

He questioned the morality of fundraising $70m for the project, when it could be spent on programmes like low cost housing.

"Do we really want to ask people for $70m plus for the church? ... It is a lot of money."

"We are trying to make sure it's not just about buildings, but it is about people as well."

David Walker/Stuff The damaged cathedral in 2015.

​Before his death in February 2016, Martin's predecessor Bishop Barry Jones approved a project to restore the central part of the cathedral, known as the nave, for about $45m.

Diocese leaders said in October 2016 that engineering work had proved the whole cathedral could be restored for about $100m.

In March last year, diocese administrator Rick Loughnan said the restoration project was "ready to go", but the new bishop would make the final decision on restoration.

Martin hoped to make a decision on the future of the cathedral by the end of the year. He said if restoration was ruled out they may consider rebuilding on a different site.

"If we did a rebuild I would want to build something that is beautiful and uplifting."

Martin's comments echo those made by Bishop Victoria Matthews about the Anglican cathedral. In May 2017, Matthews said restoration money was "better spent helping people".

"I don't think people's pain is addressed by reinstating a building," she told Radio New Zealand.

Anglicans originally voted to demolish Christ Church Cathedral and build a modern replacement, but that decision was reversed after public outcry, court challenges and political intervention.

Heritage campaigner Anna Crighton said Martin's reconsideration on the catholic cathedral was a "turnaround".

"I think there would be a lot of people out there that would be concerned about that," she said.

"All we can do is hope that he will honour the past decision that it would be restored."

Martin said he was struck by the number of people who never went into the catholic cathedral because they did not walk past it.

"We want the church to be part of the life of the city and say 'come in'. If you are further out people only go there deliberately rather than pop in like they may have done with the Anglican cathedral."

"Just because we have been on Barbadoes St for 100 plus years it doesn't mean that we have to be there for the next 100. We could look at other places if they are seen as desirable."

"If we were not going to restore then I would certainly be interested in looking at possibilities."

Martin said he wanted more information before making a final decision.

"The decision to be made is: do we restore it and what will that cost? Or do we say it was the nicest catholic church in the country but it's too badly damaged and will cost too much to restore and we'll start again?" he said.