Telstra voice outage reported by customers

Telstra mobile and fixed-line customers are complaining of yet another outage hitting their voice capabilities.

The complaints were made largely over Twitter and broadband enthusiast forum Whirlpool, with the outage appearing to be sporadically affecting customers across Australia.

"We are experiencing intermittent voice call failures and connection delays on our fixed and mobile networks -- predominantly in Victoria and Tasmania, but impacting other states sporadically," a Telstra spokesperson told ZDNet.

"We will update with further information as it becomes available."

The voice outage comes less than a week after the telco experienced an hours-long national mobile data and voice outage, which resulted in CEO Andrew Penn offering free data for all customers on Sunday, April 3.

"We are still investigating how the service disruption occurred, but our early findings show we had a problem that triggered a significant number of customers to be disconnected from the network, and as they were all automatically reconnecting at the same time, this caused congestion," Penn said.

"We will be offering all of our mobile customers another free day of data as a way of making this right. This will be on Sunday, 3 April 2016. Customers do not need to do anything to receive the free data."

Telstra last month likewise experienced a similar outage across prepaid and post-paid mobile services, which also resulted in the telco gifting all customers with free unlimited data on February 14 to provide compensation for the outage caused by "embarrassing human error".

Last month's outage took down 2G, 3G, and 4G services across the country for several hours.

Telstra chief operating officer Kate McKenzie previously revealed that February's outage had been caused by an incorrect procedure being followed after one of the telco's 10 nodes was taken down to be repaired.

"Our mobile network is set up with a number of major connection points -- what we call nodes -- around the country, which our customers connect to. These nodes are the equipment that essentially manage the flow of voice and data traffic across our mobile network. The outage was triggered when one of these nodes experienced a technical fault and was taken offline to fix," McKenzie explained.

"This normally wouldn't impact services, as we have processes in place to make sure any customers currently connected to a node are transferred to another node before it is taken offline. Unfortunately, on this occasion, the right procedures were not followed and this resulted in customers being disconnected and consequent heavy congestion on other nodes as customers attempted to reconnect to the network."

Updated at 11.55am AEDT, March 22: Telstra confirmed that the outage is affecting voice, not data, services.