The budget for Wellington's Town Hall earthquake strengthening project has blown out by $37.1 million.
The opening of the building has been delayed until 2025. It has been labelled the most complex construction project in New Zealand at this time.
The significant cost escalation, from $145.3m to $182.4m, is one in a string of many.
Since the Town Hall was declared earthquake-prone and closed in 2013, the cost of the work has grown from $43m, to $60m, to $90m, and then to $112m in 2019.
At that point it was signalled the cost could escalate even further and councillors considered an undisclosed contingency fund behind closed doors. That fund was revealed today to be worth $24.3m.
After the inclusion of some issues relating to the neighbouring Municipal Office Building and internal costs, the total budget in 2019 was $145.3m
Former mayor Justin Lester said at the time the cost was the cost.
"I'm not going to put a figure on how much is too much, we will as a council address that in the future if new information comes to hand."
The strengthening project involves lifting and propping the building to install new base isolators and extensive deep piling.
This is made even more challenging by the fact the Town Hall is a category 1 heritage-listed building.
Today council chief executive Barbara McKerrow said they have always been fully aware of the project's risks and that it could not be fully and accurately costed in 2019.
"The risks included unknown ground conditions - the building is on reclaimed land – and the full extent of the building's condition.
"Under the contract with construction company Naylor Love, the Council has retained a number of these significant construction risks for the project which are now being realised. "
This "complex web of risks" has been significantly amplified by the impact of Covid-19, McKerrow said.
The pandemic has resulted in cost escalation due to supply chain pressures, inflation, scarcity of construction resource, and continued disruption due to four lockdowns, she said.
The original construction completion date was May 2023, which has now been moved out to September 2024.
It means the building won't be open until 2025.
When it does open, it will be a world-class musical and recording venue with improved rehearsal and performance space. It will be a base for civic and community events.
McKerrow said the Town Hall was an iconic building that has been at the heart of the city for almost 120 years.
"You can only really understand the complexity of the undertaking when you see the sheer scale of the operation. We are effectively deconstructing and reconstructing a 120-year-old masonry building on reclaimed land.
"We remain committed to restoring the Town Hall to its previous glories and rightful place at the heart of the city's musical and cultural scene."