Unison has called on Kirklees Council to reverse its 'disastrous' decision to close customer service centres.
The council announced in February that two centres in Huddersfield and Dewsbury would close and be integrated into Kirklees' libraries.
The union warned the move could have a negative impact on elderly and vulnerable residents.
The council said demand for the services had fallen and reassured residents they would still be able to access the support needed.
The decision to close the customer service centres comes as part of the council's cost-saving measures and could affect up to 40 jobs.
In February the authority said it needed to save more than £47m to avoid having to declare itself effectively bankrupt.
Dewsbury's customer services team had already moved into the town's library due to maintenance works at its original site.
Unison branch secretary Mick Donoghue told a council meeting of the negative impact the closures and service changes would have on domestic abuse victims and other vulnerable people.
A petition with more than 2,000 signatures has also been submitted calling on the council to reverse its decision.
A council spokesperson said it had observed an increase in people accessing services online since the pandemic.
'The new offer will mean customers can still be enabled to access the support they need – online or in person- but this will be from within the libraries staff team.'
