Telecommunications company Spark is in the process of authenticating St John medical alarm bracelet devices back onto the network following a network fault.
Earlier today, St John New Zealand said the alarm bracelets are down as a result of an outage and there was no estimated time when the fault will be resolved.
"There is currently a nationwide Spark issue affecting the 3G network," St John New Zealand said on Facebook earlier today.
"This issue prevents cellular-based Medical Alarms from connecting to St John. If you have a medical emergency please dial 111."
However, in a statement, Spark said it became aware of the issue with a cable managed by an international carrier partner.
"This meant that some Spark machine-to-machine customers using 3G devices may have experienced congestion issues," the statement said.
"This does not impact mobile, broadband or any other Spark services. Unfortunately, this issue temporarily impacted some St John medical alarms."