TELSTRA has offered customers free data after human error left millions without mobile phone voice and data services today.

Australia’s biggest telecommunications provider is blaming human error for the “embarrassing” outage that affected millions of mobile phone services across the country today, and may cost the company millions of dollars in compensation.

In an effort to make amends, Telstra this evening tweeted customers could enjoy free mobile data next Sunday.

We’re giving all our mobile customers free data this Sunday: https://t.co/jVYK8kchWx — Telstra (@Telstra) February 9, 2016

The outage affected up to 16.7 million services attached to Telstra’s 3G and 4G networks and prevented phone calls from connecting to customers mobile phones, while other users reported complete loss of phone and data services.

Telstra confirmed the massive mobile phone service outage at 12.23pm AEDT, and did not start bringing services back online until after 2pm AEDT, though the company warned its service status page could display incorrect information due to overwhelming demand.

Telstra chief operations officer Kate McKenzie said “the correct procedure was unfortunately not followed” when working on one of the network’s 10 mobile nodes, causing massive “flow-on consequences”.

“This is an embarrassing human error. It’s not okay,” she told the 774 ABC Melbourne radio station.

“We do not like causing that level of inconvenience to our customers and we are working very quickly right now to figure out how we can provide some free data to our customers to make up for the inconvenience that’s been caused to them today.”

Telstra NSW media manager David Taylor said the node failure created overwhelming demand that affected users nationwide in a domino effect.

“The network is configured to manage this, however in this instance we had issues transferring customers to other nodes which caused congestion on the network for some customers,” Mr Taylor said in a statement.

“Services have now been restored with the vast majority of our customers now back online. We thank customers for their patience and apologise for the inconvenience caused.”

We've identified the issue and services are being restored progressively. Thank you for your patience. Sorry for any inconvenience caused. — Telstra (@Telstra) February 9, 2016

On social media, the company said it would be “more than happy” to look into reimbursement for connectivity lost after the outage after receiving a flood of complaints.

A map of outages online shows where Telstra customers were affected.

Someone @Telstra engineers are having heart attack atm, the whole Telstra (Our Biggest) network is down @tekwendell pic.twitter.com/wYs1lBwuyT — James Parker (@SkyF1FanAus) February 9, 2016

Telstra customers could still phone emergency services from smartphones during the outage, with calls using “any available network in the area”.

We’re aware of an issue affecting mobile voice and data nationally. We’re working to resolve the issue ASAP. Thanks for your patience. — Telstra (@Telstra) February 9, 2016

The Telstra outage, described as a nationwide “interruption,” affected the company’s mobile phone customers using its 4G and 3G networks.

Ironically, inquiries to Telstra representatives about the outage were met with recorded messages that phone calls could “not be completed at this time”.

As Telstra was hit with the outage, Optus also reported intermittent mobile phone connection problems around 12.40pm today, affecting phone calls, text messages and internet connections.

Its service page reported the most faults around Sydney, with some in Brisbane and Melbourne.

Customers have taken to the Telstra’s Facebook page and Twitter account to report the outage.

@zerogeewhiz We have seen a few reports of issues at present and are currently investigating further - Jessica — Telstra (@Telstra) February 9, 2016

#Telstra I am getting no data. no 4G or 3G in brisbane area on mobile. — shadow (@Yuckai) February 9, 2016

@Telstra Everybody in our office (personal accounts) has lost connection. #adelaide CBD. — Matt Magin (@AzMoo) February 9, 2016

Yo @Telstra anything happening with your mobile network in Canberra? Everyone on Telstra in my office can't make or receive calls. — Shanski (@Shanski) February 9, 2016

@jayjetjay thanks for letting us know. We have seen other customers reporting issues and we are investigating -Ash — Telstra (@Telstra) February 9, 2016

This is unbelievable. @Telstra is having outages in metro Melbourne. No wonder I can't call people... — Fab Mackojc (@fabsays) February 9, 2016

How is possible to have a nation wide outage??? Crazy from a 'Premium' service such as Telstra. https://t.co/TeEUJaFvmb — Stephen Bolger (@stephenjbolger) February 9, 2016

Telstra’s Twitter social media team took a lighthearted approach to the nightmare scenario, however, dealing with complaints from around the country with good humour.

When one person suggested someone at Telstra headquarters tripped on a cable, the Telstra reply, accompanied by a wink emoticon was: “nah, we just flicked the off switch as a bit of fun.”

@developerjack nah we just flicked the off switch as a bit of fun ;p - Dani — Telstra (@Telstra) February 9, 2016

When technology journalist Nic Healey suggested someone had dropped a bottle of bad Tequila on a delete key at Telstra headquarters, they retweeted his tweet with a reply that is was probably a bit early in the day for bad Tequila.

Somewhere at @telstra HQ, there is a bottle of bad tequila sitting on a delete key... pic.twitter.com/nPDKtOJjtN — Nic Healey (@dr_nic) February 9, 2016

Others have also seen the funny side of the outage by posting their reactions.

@kumitaguchi We are seeing both. : ) - B — Telstra (@Telstra) February 9, 2016

There's only one thing you can do when the Telstra apocalypse hits: pic.twitter.com/pxrgXmWtzK — Denham Sadler (@denhamsadler) February 9, 2016

Telstra has suffered mobile phone network outages in the past but rarely on a national scale.

In October last year, Telstra customers using Apple products suffered slow data speeds due to a breakage in an undersea cable linking Western Europe and the Middle East with Southeast Asia.

The outage occurred after Apple released the iPhone 6S and a new version of its Mac operating system, frustrating customers trying to download large amounts of data.