Staff at Nottingham's two biggest hospitals have been told there will be several months of consultation before decisions over job losses are made.
The City Hospital and Queens Medical Centre were merged earlier in the year.
Managers said there should be a clearer picture of where more than 1,000 posts will go after the consultation.
The hospital trust said it hoped to minimise redundancies by staff turnover, which currently stands at 14% per year, and a freeze on recruitment.
But opponents of the merger said that patient care will suffer if jobs go.
Nottingham University Hospitals NHS Trust was created by the merger of the Queen's Medical Centre and Nottingham City Hospital in April.
The new organisation's budget will exceed £500m a year.