Hundreds of jobs are at risk at Lancashire County Council as it tries to make £67m more in savings than it first expected.
The authority had estimated that £113m would need to be saved over three years but that has increased following the government's Spending Review.
Leader Geoff Driver said it was not known how many jobs would go and that voluntary redundancies would be the first option.
The council employs 43,000 people.
Of those 43,000, just less than half stand to be affected by the cuts. The rest are employed within education and their funding has been ring-fenced.
Mr Driver said it would be "irresponsible" to try to estimate how many jobs would be axed before they had clarity on how the cuts would affect the local authority.
Local councils will get more specific information from the government on 2 December.
Mr Driver said: "We are talking about real people here, who have families and mortgages to pay, it would not be fair if I started guessing numbers.
"But yes, we are facing a challenging time ahead, but local government always proves very resilient and we have seen and been through cuts like these in the late 1970s."
He said the council would do its utmost to protect the vulnerable in the county, but Unison branch secretary Carol Luckey said she feared those in need would be hit by the cuts.
"The savings the council will have to make are bound to have an impact on frontline services," she said.
"Take adult social care for example, I can see the age for eligibility for council help being raised.
"We are working closely with the council and having regular meetings to try and forge the best way forward. People are just shell-shocked at the moment."