A user group in is calling on them to rethink savings of £300,000 in the next financial year.
The council must save £100m by 2017 and wants £300,000 off its library budget in 2013/14.
Sandwell Federation of Library Friends and User Groups wants members to reduce cuts to a service which has made cuts of almost £880,000 in the past two years.
Group chairman Fred Barnfield said: "Libraries in Sandwell have been leaders in the campaign to reduce the impact of austerity on our borough's residents. Staff and volunteers have taken to heart key council targets aimed at helping those people most in need.
"In the past few years the service has been forced to cope with savage budget cuts. Libraries have survived because our excellent staff have worked even harder and increased flexibility.
"Along the way, a crippling 29 per cent of their jobs have gone. Nowadays visitors regularly ask why there are so few staff.
"Library opening hours were cut last year and it may well get worse this year.
"Now we are being told that we must cut another £300,000 from our budget in the next financial year. That is on top of almost £888,000 over the past two years. This is a tipping point for Sandwell's library service."
He is calling on members to vote against any proposed cuts to library services and said: "It is not a big sum in the context of the council's overall spending. I hope you agree that it is money well spent and decide to support libraries.
"If the council goes ahead with this budget reduction it will lead to further serious cuts in library hours, even fewer library staff – and the decline of a well loved and much needed service."
This month the Express & Star reported that the mobile library service would be cut from two vehicles to one from April 1 to save £80,000.
Despite cuts the number of people visiting Sandwell libraries last year rose by five per cent.
From January to December 1.76 million people used them compared to 1.67m people in 2011.
Multi million pound new libraries and the increase in activities was credited with attracting the increased numbers.
The new £2.3 million Blackheath Library opened in the High Street in May 2011 and shares the building with Black Country Housing Group. Oldbury's new £6m Jack Judge House in Halesowen Street opened in March 2011.