There are fears for the site of Nelson's new $44 million library, after recent data shows the region's coastline is subsiding at double the rate of sea level rise.
Nelson City councillor Rachel Sanson said the proposed new library site beside the Maitai River was a vulnerable location - subject to coastal inundation, river flooding and liquefaction.
Data from the NZ SeaRise programme shows many parts of the country are slowly sinking and will see more impacts within the next two decades, rather than by 2060 as previously thought.
Nelson Marlborough is among the fastest sinking areas, with Nelson's coastline subsiding at around 2-5mm per year.
Last May during long-term plan deliberations, the Nelson City Council voted to proceed with its preferred option for a new, high-specification library on the corner of Halifax and Trafalgar Streets, next to the Maitai River.
The main concerns of those who made submissions against the council's preferred option were cost, flood risk, climate change adaptation and whether a new library was really needed.
Sanson said there was good reason to question the proposed project in its current location.
"There is just such incredible potential for this but I also think that we have an immense responsibility with the level of investment that is being proposed, that we should be seriously assessing alternative sites that we know are going to be resilient for generations to come."
She hoped the council would pause and reassess the proposed library site in the context of the new data.
Nelson City Council chief executive Pat Dougherty said the council welcomed the information provided by the SeaRise NZ project and intended to take account of the changes in further flood mitigation work in the CBD and other impacted areas of Nelson.
He said the data was well-timed, as the council would be talking to the community next month about how sea level rise would affect the coast and the consequences it would have for the community and economy.
Council staff were currently taking stock of the new data and planned to respond to it in more detail in the coming week.