Almost $90 million is being poured into Wellington's Town Hall to earthquake-strengthen it.
The more than 100-year-old building has been closed since the 2013 Seddon earthquakes and was damaged further in the Kaikoura earthquake last year.
Mayor Justin Lester announced today that the hall would be brought up to 100 per cent of the building code and would be ready to reopen in 2021.
He said the original cost for the project was $58.5 million but the new price was closer to $85 million.
"The original proposals didn't anticipate bringing it to 100 per cent of building code but we want to do this once and we want to do it property.
"In the past, we've looked at schemes that got it up to 60 per cent of code but it's been strengthened in the past, most recently in the 1990s but where did that get us? It didn't get us to a good enough standard that we're going to actually have a lasting building for the future."
Lester said it had been clear for a while the previous plan wasn't going to be enough to restore the building.
"It's not going to become cheaper in the future and building a replacement venue would be much more expensive and lack the tradition, heritage and prestige of the town hall."
Lester said the extra cost also reflected the complexity of the project, a buoyant construction market and continued seismic uncertainty after the Kaikoura earthquake.
He said it was worth spending the money on Wellington's "beloved" town hall.
"This is without doubt my favourite building in the city."
The building was completed in 1904 and cost £68,000 at the time.
Lester said since then, the hall has seen some historical moments.
"The Beatles performed here, the Rolling Stones, the New Zealand Symphony Orchestra had their first official concert right here in Wellington's auditorium as well."
Wellington City Council's civic administration building is nearby the town hall and a decision is still being made whether to demolish it following the Kaikoura earthquake.
Lester said the civic administration building's fate would not affect the Town Hall project.
"That will have no impact whatsoever."