The cost of reinstating the Christ Church Cathedral and constructing new attached buildings is now $154m dollars.
The building had lain in ruin since the Canterbury earthquakes, with strengthening work now underway.
When the Anglican Synod voted by a narrow majority in 2017 to reinstate the building, the estimated cost was $104m.
Prior to voting the then government pledged a $15m taxpayer contribution, as well as a $10m loan.
The Christchurch City Council also committed $10m in ratepayer funds for the project if Synod agreed to reinstate the building.
After Synod voted to reinstate the building, a Christ Church Cathedral Reinstatement Trust was set up to fundraise the money needed.
But now building work was underway, the cost of the project increased to $154m, about 48 per cent higher than originally estimated.
The Anglican Bishop of Christchurch, Peter Carrell, said the $154m was to finish the "entire Cathedral quarter".
That included the "reinstated and enhanced" Cathedral, landscaping, two new external buildings and associated costs.
"The reality is that this vision comes with a cost," said Bishop Carrell.
"We've known for some time that the overall cost would exceed the $104 million estimate developed by the Cathedral Working Group in 2016.
That was based on an early engineering assessment of reinstatement that did not meet the full scope or vision of the project," he said.
"It has been a logical, robust, well-thought-out process and it has taken until now for us to really pin down the look, feel and function of how the Cathedral Quarter will really be – and, as such, get a reasonable cost estimate for this stage of design."
The Herald asked Bishop Carrell if he, as Bishop of Christchurch, was comfortable with this much money being spent on the Cathedral, especially given the financial challenges facing many New Zealanders in 2020.
"I'm comfortable with $154m being spent on the Cathedral because the Cathedral has a vital role to play with the renewal of Christchurch city," he said.
"It's a lot of money on a church building...but one of the reasons why the government, the council and the public are keen for us to reinstate the building is the public contribution to Christchurch."
Former Anglican Bishop, Victoria Matthews, originally recommended demolishing the cathedral and building a new one, saying the church had far great challenges to tackle including child poverty and climate change.
The Christ Church Cathedral Reinstatement Trust chairman, Peter Guthrie, said $51m still needed to be fundraised.
"The fundraising target is ambitious yet achievable, and we are confident that a wide range of people here in New Zealand and from around the world will provide support.
"The good news is with over $100 million already raised, we are already two-thirds of the way to our goal," he said.
Concept designs for the Cathedral were also released today. It included a new visitors centre north of the Cathedral, which featured a café.
A lowered courtyard would include retail space and a museum.
On the south side a "Cathedral Centre" would be built which would include "gathering spaces" and offices.
Work on the Cathedral itself - including stabilisation would cost $127.4m, the Visitor Centre and Cathedral Centre $15.7m and a new tower $11.2m.
"This is an investment in the future of the central city, Christchurch and Canterbury. The Anglican Cathedral is an iconic building at the heart of the city and the seat of our Anglican faith," said Bishop Carrell.