The workers met with legislators, legal experts and community leaders in Raleigh to ask that the hospital's opening be delayed a year.
“I think we make a mistake if we don't listen to people who actually work in those situations,” said Rep. Larry Bell, D-Sampson.
Workers said the new hospital will be understaffed and dangerous.
"The place is not safe at all,” Dorthea Dix Hospital worker Margaret Pettifored said.
"Under-staffing, mandatory overtime. We have an increase in patient and staff injuries," Bell said.
The workers also rallied Thursday outside of the Wake County Office Park on Carya Drive, where their meeting was to take place.
They said existing problems at Dorthea Dix will only be exacerbated when the Butner facility opens on July 1. Dix will close on the same date, and patients will be moved to the new hospital, beginning in mid June.
"We always need more help,” Pettifored said.
Central's opening was delayed once in January after patient advocates complained the move was happening too fast and an internal review found 30 types of hazards at the new hospital.
DHSS officials admitted that staffing will be a challenge in the new hospital, but said they will be able to meet it.
"Patients are always first,” said Larsene Taylor, a health-care technician at Cherry Hospital in Goldsboro and chair of the North Carolina Public Service Workers' Union chapter for workers in the state Department of Health and Human Services.
The state will keep 60 beds open at the Dix campus for about three years to help with the transition to the new hospital.
The entire state's mental health-care system has been under fire lately amid years of claims of wasted money, inadequate services and patient neglect and abuse.