Southampton's librarians have held a one-day strike over plans to replace some of them with untrained volunteers.
Staff protested outside Portswood Library, Bitterne Library, Woolston Library, Shirley Library and Central Library from 0830 BST on Monday.
The council said it was responding to "difficult economic times ahead".
But librarians believe volunteers lack their skill and commitment. The city's Labour MPs John Denham and Alan Whitehead also attended the protest.
Lisa Jones, from the union Unison, told BBC News: "If [volunteers] don't want to come in when it is raining, they don't have to come in.
"If it is snowing [librarians] always come in. [Librarians] always open up the libraries and give a very good service."
Councillor John Hannides, Southampton's cabinet member for leisure, culture and heritage, said: "I am very disappointed that library staff have decided to strike.
"Our proposals do not mean that our staff will lose their jobs. By taking the action we have managed to avoid this happening, unlike other authorities.
"We have skilled and able staff in the service and in the difficult economic times ahead, it seems sensible to make greater use of volunteers to support them in delivering a quality service."
Some Hampshire County Council librarians and lecturers from Solent University also took part in the demonstration.