The trust has made the move after increased demand in patients requiring emergency care on Wednesday caused it to declare a major incident at the facility.
Patients said they faced waits of almost 12 hours and staff likened the scenes they faced to a war zone.
The backlog of patients - caused by a recent spike in the number of people attending - came despite the absence of a flu epidemic, snow or other major contributing factors.
The major incident plan called in extra staff to deal with the scores of patients left on trolleys while waiting to be treated.
Some people were also diverted to other hospitals.
Following the incident, staff protested about the "crisis" and Health Minister Edwin Poots was booed by those protestors when he visited the hospital.
The major incident ran for four hours until midnight on Wednesday.
On Friday a spokeswoman for the hospital said: "Belfast Trust's emergency department is working normally.
"The trust has put in place contingency arrangements and created additional capacity for the coming weekend should it be required.
"Our clinical and managerial staff work in tight partnership to relentlessly focus on alleviating pressure in the emergency department and they are committed to ensuring the Belfast Trust delivers the best possible care for our patients."
One of Northern Ireland's top medical officials has praised the Belfast Health Trust and the work of medical staff for their actions following the incident.
Head of the Health and Social Care Board, John Compton, said the staff and management, dealt appropriately with the situation.
He told UTV Live Tonight: "I don't think it was a crisis, there was a particular set of circumstances that occurred and I think the trust acted entirely properly.
"It declared the emergency, that's a major incident, it triggers extra staff coming in, it triggers the whole of the health and social care system to support it.
"When the divert went to the Ulster Hospital to allow the Royal to recover, it was very quiet and calm.
"People have their perceptions. I am certainly sure that when the incident was declared at 8pm and ran through to 12am for four hours it was very difficult.
The point I would make is that when we declared the incident, the question to ask is that did the incident declaration work and it did.
He added: "As with all major incidents we will look at it again and learn from it.
"But people should be reassured from the fact that when you call a major incident, you do get a result, you do get control and you do get a restoration of how departments are working."
Mr Compton said it wasn't just the number of people at the hospital, but the nature of the "degree of illness" that staff had to deal with.
"Normally we admit people on a one in four basis, but on Wednesday, it was closer to one in two basis, that's what caused the difficulty, that's why at one point there was 40 people on trolleys."
Louise Skelly from the Patient and Client Council said there needed to be a change in the system to ease the pressure on the health service.
She added: "People feel there are barriers to getting access to GP out of hours, or there are delays, for example in getting care for sick children, so the only way to get treatment, or to get admitted, is to attend the emergency department.
"The whole system needs changed.
"People with long term illness or the frail elderly feel that doctors should have the ability to admit them directly to hospitals."