Hospital bosses in Leicester have admitted patient care may be affected after being told they need to slash their budget by another £15m.
Chief executive Peter Reading says staff are in for a hard time
This is on top of the £22m which was cut from the city's three hospitals earlier this year.
Managers say savings will help primary care trusts, which buy services from the hospitals, to balance their books.
Redundancies should be avoided but the hospital trust admits staff are in for a tough few months.
The University Hospitals of Leicester NHS Trust will meet on Thursday to discuss how to save the money over the next five months.
Chief executive Peter Reading said the trust was on course to balance its books but had been asked to plug financial gaps in other parts of the NHS.
He said: "We're going to do it in a number of ways. We're looking at staffing - we've got a vacancy freeze now which we haven't had before and we're going to rein back incredibly tightly on the use of bank and overtime staff on our wards.
"We're fortunate that on our wards the vacancy level is the lowest ever. So wards are well staffed for the most part."
Pressure on staff
Mr Reading said patient safety was, and would continue to be, the number one priority.
"But I'm particularly concerned about the wards which look after our most vulnerable patients, older patients. Those are the wards we're going to be protecting.
"Staffing is going to be tighter than it would otherwise have been and that puts more pressure on our existing staff."
He added that the trust would be keeping a close eye on its spending.
"We'll be monitoring it day by day to ensure we don't slip."