Derbyshire councils may have to merge: John Harrison
Serious consideration will have to be given to reducing the number of local authorities in Derbyshire, according to a senior county councillor.
Conservative John Harrison, cabinet member for finance, said estimates of future council spending were "scary".
Social care is projected to account for 67% of the council's budget by 2020, an increase from 40% compared with 2012.
But other council leaders said reducing the number of authorities would harm local decision-making.
Mr Harrison told fellow councillors that by 2020, county councils were expecting to spend 67% of their budget on social care, 18% on the environment, with just 15% for everything else.
He said: "There have got to be some radical changes in the way councils are run.
"Against the background of the national debt... consideration will again be given to some form of rationalisation between county councils and districts and boroughs."
Local authorities receive income from council tax, which has been frozen in Derbyshire for two years and from the government, which is reducing its grants.
But other leaders said getting rid of borough and district councils would not be sensible.
Bob Wheeler, Conservative leader of South Derbyshire District Council, said: "I very much doubt at the end of the day whether you would find savings."
He added that "local democracy and local input into decision making" would be lost.
Labour leader at Derbyshire County Council Anne Western said she was surprised Mr Harrison had raised the issue.
She said: "A lot of councils are already working jointly.
"I think we do need to work together to look at priorities but I don't think looking at structures is the answer to this problem."