The 15-room facility is part of an $8 million redevelopment of the complex.

Patients in the existing mental health unit at the hospital will move into the new rooms on Tuesday.

Work will then begin to upgrade the former unit into private rooms for medical and surgical patients.

The new unit has consulting rooms, a dining room, group therapy/lounge room, a designated Transcranial Magnetic Stimulation room, outdoor areas, day group therapy areas, a gymnasium and a sensory room.

The therapy room can be divided into three separate areas.

It can be accessed from Wolsley Street separate from the main hospital entry on March Street.

The wing has commanding views over Orange and to Mount Canobolas.

Dr Tristram Duncan, the clinical director of the Dudley Clinic, said they treated a range of mental health disorders.

"We mostly concentrate on mood disorders. Those would be things like depression or bi-polar disorder," he said. "We provide service for anxiety disorders, personality disorders and psychotic disorders."

He said patients would attend the facility from across NSW.

Dr Duncan said private mental health clinics were "quite light on the ground" in regional areas.

Dudley CEO Paul McKenna said the clinic was part of expansion work at the hospital that would have 62 beds when completed.

Almost all of the beds will be in single rooms.

He said work was also continuing on a $4 million 'cath lab', a specialist room with diagnostic equipment for examination of the heart, at the hospital.

Mr McKenna said it was "very exciting" to finally see the clinic completed.

"The Dudley Clinic has a really good feel to it," he said.

"It has a lovely aspect and is light-filled and spacious that considers the comfort of the patients and staff.

"The Clinic will have a private entrance at the rear of the existing hospital, to ensure patient privacy is maintained."

Mr McKenna said the clinic had ongoing services.

"We offer outpatient programs to give patients the best possible outcomes after what is commonly a one-to-three week stay at the Dudley Clinic," he said.

Mr McKenna said people needing care should call EasyAccess on 1300 855 249.

Dudley Private Hospital is run by the Ramsay Health Care group.