Part of the emergency 111 system is down.
Police say the text service that allows those with hearing or speech difficulties to contact emergency services has not been working since 4.30am today.
Text messages that are then directed to the ambulance and fire services are also affected.
Police said people registered to use the text service would need to get help to call the usual 111 number.
They said they were trying to get the system back up and running but could not say how long that would take.
The 111 text service gets about 10 messages per week.