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."