The restoration of the Christ Church Cathedral has become one of the city’s most contentious post-quake projects, with supporters arguing it is a vital piece of New Zealand’s heritage and critics questioning whether taxpayers should contribute more money to close a significant funding shortfall.

Ahead of Prime Minister Christopher Luxon's visit to Christchurch on Wednesday, Nadine Roberts breaks down the numbers, the politics and the funding gap at the centre of the debate.

So far a total of $90 million has been spent on the planned partial restoration and reopening of the building, led by The Christ Church Cathedral Reinstatement Trust (CCPT).

Approximately $40m came from the church’s insurance payout, $25m from taxpayers and $24m from donors.

Ratepayers have also contributed $3m to the rebuild, and will eventually pay $7m once restoration continues.