Some hospitals in NI may have to close to help balance the books over the coming years, according to a report.
The research commissioned by the Health and Social Care Board warns a financial crisis is looming unless tough decisions are made.
Other controversial suggestions include a charge for patients going to A&E or their GP.
Health minister Michael McGimpsey said he can not support some of the proposals.
He said patients would find them unacceptable.
But Mr McGimpsey also warned that on the basis of the draft budget, some change will be inevitable
"It is clear that very difficult decisions will have to be made regarding our health and social care service over the next few years. It is simply impossible to continue to deliver services the way we currently do with the funding available."
The minister has warned that 4,000 jobs could be lost in the Health Service because of budget cuts.
To provide an efficient service, officials said they needed £5.4bn by 2015 - instead they are to get £4.6bn - a shortfall of £800m.
The research commissioned by the Health and Social Care Board was carried out by management consultants McKinsey.