People in Nelson are being asked where a new multi-million-dollar community hub, library and civic space should be built in the city centre.

Nelson City Council said the project to replace ageing public buildings would be one of the biggest investments the city would make in a generation.

The council was proposing three options: developing the current Civic House and the adjourning Savings Bank and State Advances sites; or building a new hub, library and civic space in Collingwood Street - or in Church Street.

The Civic House option would cost an estimated $73.3 million, Collingwood Street $74.1 million, and Church Street $88.2 million.

The council said all three options had trade-offs and would affect rates because it had only budgeted $68.4 million for the project.

Nelson mayor Nick Smith said it made sense to combine the library with the civic hub.

"A single building combining library and civic services is more efficient and will provide a vibrant and flexible hub for our city. The key question for council - on which we are seeking the public's views - is whether we upgrade and expand the existing Civic House or build new on one of two alternative sites," he said.

"It is also an important part of revitalising our city centre. A well-located civic facility can bring more people into central Nelson, support surrounding businesses, strengthen connections between key city destinations and help attract further private investment."

Smith said the council was conscious of cost-of-living pressures and the need to deliver good value for money for ratepayers.

Deputy mayor and city revitalisation chair Pete Rainey said people were being asked to consider more than the initial construction cost.

"This is more than a building project, this is an intergenerational investment in learning, culture, community connection, local democracy and the life of our city centre," he said.

"Each option would influence the future of central Nelson in a different way. I encourage everyone to consider this consultation with ambition and enthusiasm and consider which location would make the strongest contribution to a welcoming, active and thriving city centre for generations to come."

The council said the Elma Turner Library and Civic House buildings had ageing systems and increasing maintenance requirements, and continuing to rely on repairs and short-term fixes was not viable over the long term.

Consultation will run for six weeks, from 27 July to 6 September.

Following consultation, councillors will consider public feedback alongside technical, financial and planning advice before choosing a location and confirming the associated budget for inclusion in the Long Term Plan 2027-2037.