Ambulance crews from the Republic were drafted into Northern Ireland for a second night in a row on Saturday night.
The issue arouse after the Northern Ireland Ambulance Service found itself stretched beyond capacity.
On Saturday, a crew from was based at Altnagelvin Hospital in Derry.
While on Friday another crew had to be based at Newry Ambulance Station.
Both services have an understanding they will help each other out in special circumstances.
A spokesperson for the Northern Ireland Ambulance Service says they were ten crews short on Saturday and they also had to use 8 private and voluntary ambulances to deal with non life threatening cases.