Some Wigtown residents are unable to make phone calls, including those to 999, following a fire in a phone exchange.
All landlines are out of action in the area. Members of the public who do not have access to a mobile phone and need to make an emergency call are advised to contact a neighbour, relative or friend.
Police Scotland say they will also have more officers on hand to help whilst phone lines are down.
Residents who are aware of vulnerable people in their communities are asked to check their welfare and offer help where needed.
BT say they are working to restore normal phone services as soon as possible, but this could take several days.