Phased closures are planned to start from 21 January and the trust said it would result in a £325,000 saving for the current financial year.
UHMBT said it had worked to increase the number of virtual beds – a new model designed to support patients in their own homes – as well as other measures to redirect patients to appropriate services.
A spokesman said: “The simple fact is that whilst the plans to reduce the bed base are the right ones, we ideally wouldn’t be doing it during winter with the operational issues this period brings.”
A further 24 beds are set to close at the Royal Lancaster Infirmary, which is also managed by UHMBT.
The trust added no jobs would be lost as a result.
Scrogham said the government had helped the trust become more financially stable, after facing challenges in the past.
“The trust needs to think carefully about the long-term implications of decisions it makes, they will be held accountable,” she said.
The Department of Health and Social Care (DHSC) said the government had provided “record investment” in the NHS.
A spokesperson said: “Whilst we expect all NHS trusts to be financially responsible and to maximise value for money for taxpayers, we will ensure those which require additional support get the help they need.”