County councillor Sue Woodward, who represents Burntwood, has expressed concerns that she has been sent a document that outlines a reduction in hours at the town's library just days after bosses launched a 12-week consultation.
Thousands of people are expected to take part in the review over plans to get volunteers to run 24 of the 43 libraries in Staffordshire.
Hours at libraries earmarked to continue to be run by the council could also be slashed depending on responses from the public.
But Mrs Woodward has been sent a document that says Burntwood Library on Sankeys Corner will only open late on one evening a week – down from two currently – and open later on a Saturday.
She said: "I am very concerned that this consultation is not as transparent and open as it is being made out to be.
"It appears that in some areas that decisions have already been made.
"These changes may only be minimal compared to the threats hanging over some libraries but it is worrying."
The council has said it is waiting until the end of consultation before it makes any decisions and that opening hours of all libraries are under review.
Mike Lawrence, Staffordshire County Council's cabinet member for communities and localism, said:
"Libraries have already changed a great deal in the last decade, but user numbers are still falling.
"We need to change, radically, over the next three years to reinvigorate our libraries so they are better used within their communities, as well as developing the online service, but I must emphasise this is not a closure programme – we understand their value and their importance and we are committed to them remaining a valued part of local life."