Telstra's voice outage across its national mobile network on Tuesday was due to an issue with a media gateway in Victoria, which failed to connect calls.
The outage, which the telecommunications provider has repeatedly emphasised affected fewer than 3 percent of its customers, was resolved within about an hour of going down.
"The disruption today, which impacted less than 3 percent of our mobile customers, was caused by a card failure in a media gateway in Victoria, which meant certain calls could temporarily not get through. The media gateway allows the calls to connect," a Telstra spokesperson told ZDNet.
"While small, we appreciate the impact this outage had on the customers affected, and we apologise to them."
The spokesperson added that Telstra is recommitting to a "major" network review.
"While we have the leading network in Australia, like any of our global peers there will always be issues that arise in such a large and complex technology environment.
"We are committed to redoubling our efforts on resilience in the network, and part of that is conducting a major review in relation to the outages from last week and February."
Earlier on Tuesday, Telstra mobile and fixed-line customers had complained over Twitter and broadband enthusiast forum Whirlpool of yet another outage sporadically affecting their voice capabilities primarily affecting customers in Victoria and Tasmania.
"We can confirm the issue is now resolved," the spokesperson said.
"Today's interruptions lasted for about hour and impacted less than 3 percent of our mobile customers, mostly in Victoria and Tasmania, with intermittent issues in other states."
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".
Meanwhile, Vodafone Australia is attempting to take advantage of Telstra's third outage by spruiking its own network and offerings.
"We know how important it is to stay connected, so if you're having trouble with your network, we invite you to come on over to Vodafone," said Vodafone director of Sales Ben McIntosh.
"We know 'free data' days are all the rage right now, which is why Vodafone offers two months of unlimited data to post-paid voice customers when they join or upgrade."