Seventeen members of staff have been suspended at a hospital that treats young people with mental health needs.
It follows reports some nurses and healthcare assistants used non-approved techniques to move patients at Middlesbrough’s West Lane hospital.
Tees, Esk and Wear Valley NHS Foundation Trust said it took the allegations extremely seriously.
It has launched an investigation, which is also being overseen by the Care Quality Commission and NHS England.
Concerns were raised in November about West Lane Hospital’s Westwood Centre, which offers low secure adolescent inpatient accommodation.
They centred around claims staff used techniques for moving patients which were “not taught and not in line with trust policy”.
Additional staff have been been temporarily assigned to the Westwood Centre while the investigation was ongoing, the trust said.
Elizabeth Moody, the trust’s director of nursing and deputy chief executive, said: “We expect staff to show respect for the dignity and wellbeing of patients, and we take allegations that could suggest otherwise extremely seriously.
“Our patients are our priority and we responded quickly to these concerns.”
She added she was not able to give further details while the investigation was ongoing.