The former Health Minister has branded the decision to overhaul A&E services in Belfast and Lisburn as an attempt to save money that will put patients at risk.
Michael McGimpsey has criticised his successor, Edwin Poots, after he revealed the A&E at Belfast City Hospital could close by October.
Mr McGimpsey, a UUP MLA for South Belfast, has urged Mr Poots to review the proposal - warning the move could lead to chaos in hospitals across Belfast.
He said: "The plans outlined by the minister will leave the Royal and Mater having to cope with up to an extra 50,000 patients from the City, as well as those who may come from Lisburn as a result of reduced hours at the Lagan Valley.
"I believe that the decision by the minister to close the City Hospital A&E is putting money before patients. No decision should be taken on A&E services within the Belfast area until the new A&E unit at the Ulster Hospital and critical care unit at the Royal Hospital are completed," he said.