Up to 200 posts are being cut from the Great Western Hospital in Swindon.
The Swindon and Marlborough NHS Trust which runs the new private finance initiative facility said it needs to save nearly £6m this year.
In a statement it said: "We will do everything we can to minimise the effect on patients."
It is hoped 99 jobs will be go through natural wastage however compulsory redundancies have not been ruled out, and a further 99 will be frozen.
The trust intends to:
- close one operating theatre
- close nine hospital beds
- use fewer agency nurses
- review how minor injuries are managed and treated
"Our members are angry, shocked, surprised, disillusioned and demoralised in differing amounts," said Kevin Brandstatter of the GMB union.
"Every trust has been put in this position by government policy.
"This hospital in particular is governed by a private finance initiative so the hospital isn't owned by the trust it's owned by Carillion who charge a rent for services and they get paid first whatever happens.
"We will do everything we can to fight these redundancies," said Mr Brandstatter.