As many as 1,400 posts at Manchester's biggest hospital trust could be lost over the next four years because of government cuts.
The posts that Manchester Central University Hospitals Foundation Trust is considering freezing include medical jobs.
The trust is cutting £30m a year but managers have only identified where £17m will be saved so far.
The trust is responsible for Manchester Royal Infirmary, St Mary's Hospital and the region's eye, dental and children's hospitals.
Most job losses will come through not replacing staff who quit - around 1,200 workers leave the trust every year.
However, bosses have said that they are not ruling out redundancies, adding that they are negotiating cheaper deals with suppliers and trying to cut fees paid to recruitment agencies by filling key skilled posts with permanent staff.
A trust spokeswoman said of the job freezes: "This is just one thing we're looking at, it's not signed off."