A council is being “far too hasty” in its plans to close eight libraries and reduce the opening hours of those remaining, a union has said.
Hampshire County Council wants to save £1.76m from the library service, putting 50 jobs at risk.
Unison union said it had been “inundated” with complaints from staff.
The authority said it understood their concerns but was using a “transparent and fair selection process”.
Under the proposals, libraries will shut in Blackfield, Lyndhurst, Fair Oak, South Ham, Elson, Horndean, Lee-on-the-Solent and Odiham.
The remaining libraries will have their opening hours reduced by about 20%.
In a “mandatory” consultation form, seen by the BBC, all library service staff are being asked to state their three preferred library locations, as well as set out their skills.
Callum Williamson, Unison Hampshire’s branch secretary, said the union had been “inundated with complaints” from its members.
“Hampshire County Council is being far too hasty,” he added.
He said consultation was not due until 5 November and that staff “must have genuine opportunities to present alternatives to these unpopular and controversial proposals”.
“Asking staff to choose new shifts and working locations now gives the distinct impression that decisions for the future of the service are already set in stone,” he said.
Hampshire County Council said it understood the proposed changes “may be of concern” to staff but was “seeking to alleviate these by using a transparent and fair selection process”.
It said consultation on proposed staffing changes was needed to “align” wider decisions about the planned closures.
It said no decisions would be made until after the consultation had concluded and that feedback from affected staff and unions was “encouraged”.
It previously said it hoped to avoid compulsory redundancies.
The proposals, which also include the council’s withdrawal of support for Lowford, Milford-on-Sea and North Baddesley community libraries, would provide “the best possible library service within our means”, the authority had said.