Flintshire councillors have been told that the authority needs to make £12m of cuts in the next financial year.
A report presented to the authority's executive board said the "myth that 2011/12 will be a much easier year than expected should be exploded".
The report says the most "contentious" areas which could face savings include schools, libraries, leisure, social services and charging policy.
The council's final budget proposals will be considered in February 2011.
The council's financial position for the next financial year is better than it had forecasted.
However, the report warns that "this does not mean that setting the council fund revenue budget for 2011/12 will be any less challenging for us".
It has already identified about £9m of potential savings, but needs to find up to £3m more by early next year.
Factors blamed on the need for efficiencies include a reduction in its funding , inflation, "local pressures," the economic downturn and others.
Councillor Bernie Attridge, deputy leader of the opposition, said councillors had expected cuts, but said he had "great concerns" over how they would be implemented.
He added: "One of the aspirations that's been talked about is £20m for new county offices for the council.
"How can this even be considered when we're talking about closing sports centres, libraries, and taking free transport from the elderly?
"I believe there could be more cuts among senior management. When we have people earning £100,000 plus, we should be looking at them, rather than closing sports centres.
"It's going to mean more job losses and I fear for our staff.
"They seem to be going for people at the bottom of the scale rather than the top."