Senior officers at Cornwall Council have been told “stringent measures” will have to be taken if an overspend of £14.9m is not brought under control.
The move could mean the council will not take on any new commitments or services if savings are not made by the end of this month.
The message was delivered by the council’s deputy leader councillor David Harris at a meeting of the Conservative cabinet.
A council performance report for the second quarter of the 2023/24 financial year shows an overspend of £14.9m.
Mr Harris said he had written to the government in “fairly blunt terms” to express the council’s concerns about the financial sustainability of local government in general - and Cornwall in particular.
At the council meeting Mr Harris said: “You can see from the Q2 report the tide is yet to turn on increasing expenditure.
"I would ask all the overview and scrutiny committees to look again at the areas of concern before the calendar year is out."
Mr Harris said if the situation did not change, councils faced a funding gap of about £4bn over the next two years just to keep services at current levels.
“As the Q2 performance shows starkly, Cornwall Council is not immune from those financial strains and stresses,” he added.
He said a budget and savings review group had been set up to identify areas where the overspend could be reduced.
“All senior officers have been made aware that if overspends cannot be brought under control by the end of this month some fairly stringent measures will be introduced to reduce spending, including no new commitments being taken on without being approved by the review group," he said.
The council announced in September it would need to cut some services as it faced “difficult decisions” to achieve nearly £75m in savings by 2028.