The Australian Communications and Media Authority said in a statement on Monday that Telstra had failed to ensure some 1433 calls went through to the operator due to problems triggered by a fire in an inter-state cable pit. This was compounded by network software failure.
Telstra has to comply with the Telecommunications (Emergency Call Service) Determination 2009 and the Emergency Call Service Requirements Industry Code C526:2011.
Communications Minister Mitch Fifield said a report released by his department into this incident and one other, when a large volume of calls were directed to triple zero from the Vocus network on 26 May, had resulted in 11 recommendations seven of which apply to Telstra.
“This was the first serious disruption to the triple zero service in more than 50 years. With the measures the government is putting in place, Australians can feel confident the service will have greater safeguards in times of need.”
The ACMA said it had accepted a court enforceable undertaking from Telstra in which it committed to improving the redundancy and diversity of its network, developing new communication protocols to be used in the event of another disruption and benchmarking its systems against international best practice.
"Triple zero is the lifeline for Australians in life-threatening or emergency situations. Community confidence in the emergency call service must be maintained," said ACMA chair Nerida O’Loughlin.
"The actions Telstra has already taken, and is undertaking, will help strengthen the emergency call service and minimise the risk of another disruption to this critical service."
The ACMA said it was also reviewing rules governing the emergency call service to ensure they were as robust as possible and that they imposed clear, consistent and appropriate obligations.
"Given the critical nature of the Triple Zero service, the ACMA takes matters about access to the service very seriously," O'Loughlin said.
"The review will help ensure that the rules for the emergency call service remain current and effective."