The Northern Ireland Ambulance Service has said that it is experiencing difficulties with its telephone system.
It said that 999 calls were being re-directed to mobile telephones held within ambulance control headquarters.
It said: “We have implemented our contingency plans whereby BT will divert 999 calls to dedicated mobile phones held within ambulance control or alternatively to Scottish Ambulance Service who will then relay the call to us.
“We are currently working with BT to identify and remedy the fault.”
It advised the public only to contact them if it was in the case of a genuine emergency.