Making Wellington's central library earthquake-safe could cost more than $100 million, says the city's mayor.
Mayor Justin Lester said his first priority was to strengthen the existing building, rather than pull it down.
Mr Lester said initial advice showed getting it to 100 percent of code would likely require base-isolation - and that all the options were expensive.
"Potentially more than $100 million, but with uncertainty around it. So that's very early level concept figures and that's why we need to do more work, and that's why it also brings in the question of the future of the building."
Mr Lester said he was not interested in partnering with a private developer to bring down the costs of strengthening or rebuilding, because libraries were a public service and should remain in public ownership.
But if he got another term in office, Mr Lester said he would be pushing for a regional transport authority to take over the work of public transport, parking, and roading.
Those functions are performed by local and regional councils, with funding and assistance from the NZTA.
The region-wide authority would be governed by a combined committee of elected councillors but local councils would still own the assets, he said.
Mr Lester said that would let local councils have more of a say in transport projects.
"We have a whole lot of people relying on public transport but we've had little insight into, or ability to participate in, the operations of the buses for example and that would give us the opportunity to have more of an insight and to have more of a collective say for Wellington."