The number of health trusts in the North is being slashed from eighteen to five under changes introduced today.
A single umbrella organisation will cover Belfast, under the reorganisation of health and care services through the Review of Public Administration.
Up to 1,700 jobs are to be axed as part of cost-cutting measures.
A spokesman for the new trust said: “The aim is to improve the efficiency of the service. Most of the jobs will go as part of natural redundancies.”
The new bodies will be known as the Belfast. South Eastern, Southern, Western and Northern Trusts.
Managers also hope to avoid compulsory redundancies through redistribution of jobs.
The Belfast Health and Social Care Trust comprises the City, Royal, Mater, Greenpark, North and West Belfast, and South and East Belfast trusts.
It will be one of the largest health and care organisations in Europe and will provide most of the specialist services available in the North.
The chief executive of the Northern Trust, Norma Evans, said she would be losing around 300 staff but added that those affected would probably be veterans who were happy to go.
“We will have a single director who will be responsible for care, whether that be domiciliary care or intensive care. It should be possible for us to make this markedly simpler for patients, more responsive and the aim will be to deliver better services for health.”