Children's Services and transport schemes run by Nottinghamshire County Council are facing cutbacks after government grants were withdrawn.
Cash earmarked for children's services has been cut by £3.7m and plans for integrated transport system have suffered a £2.6m blow.
In total the county authority has lost £8m funding as measures to tackle the national deficit kick in.
A spokesman for the union Unison said vulnerable people would suffer.
The council said it would spend "within its means" and consider how to make savings.
In a statement, Councillor Reg Adair, who is responsible for finance and property, said: "The council was expecting reductions to our government grants in light of the national debt that central government is currently tackling.
"We will continue to spend within our means and will be looking at our budget for this year to identify where we will make the necessary savings."
Unison spokesman Ravi Subramanian said: "We're at a bit of a crossroads with a choice of a society based on a fair tax system or a free-for-all for the super rich.
"In announcing these cuts the government are targeting vulnerable people and protecting the wealthy."