The issue is also affecting eftpos terminals on the Optus network, hospitals, and Uber drivers who have been unable to operate the app.
Ramsay Health Care, which operates 73 private hospitals and day surgeries across Australia, said its phone lines were down as a result of the outage.
NetBlocks said metrics show Optus mobile services are down across much of Australia, leaving millions of customers unable to make calls or access internet since early morning.
“Ramsay hospital phone services are being impacted by a national outage of Optus telecommunications. At this time, we are unaware how long this outage will continue,” it said in a statement on Facebook.
“If you need to contact your local Ramsay hospital, please direct inquiries via the contact form on the local hospital’s website.”
Melbourne’s Northern Health district also took to Facebook to inform patients that all phone lines into its hospital campuses had been affected.
“This includes phone lines into Northern Hospital Epping, Broadmeadows Hospital, Bundoora Centre, Craigieburn Centre, Kilmore District Hospital, and Victorian Virtual Emergency Department,” it wrote.
“We apologise for any inconvenience.”
The NSW Poisons Information Centre is also uncontactable due to the outage.
“During this time, please call the Westmead Children’s Hospital switchboard on 02 9845 0000 to be transferred to a Poisons Information Specialist. In an emergency call 000,” it said.
Communications Minister Michelle Rowland said she is in touch with the telco which is throwing its “full resources” at the problem. She said Optus did not believe the outage was the result of a hack.
“I think it’s been a very anxious morning for many Australians so far,” she told ABC Radio.
“It appears to be nationwide affecting broadband services and mobile … that is what we call deep in the network.
“[That is] certainly one that would require the full resources of Optus just to be thrown at it at pace.”
Abraham Golski, who operates Abe’s Coffee Supply in Sydney’s inner-west had to delay opening his café on Wednesday morning due to the outage.
“I had to find out searching on the internet, [Optus] didn’t send a notice, message or email,” he said.“I cannot accept card payments, how frustrating.”
One Optus customer, Annie, told ABC Radio she found out about the issues through her cat, who is fed through an automatic Wi-Fi feeder, and missed being fed due to the outage.
International roaming customers are also being hit by the outage.
Optus user Kim Boey is in Greece and said her roaming stopped working about 5pm Greece time.
“I am trying to turn off overseas roaming and two hours later, it is still not completed. It is 9.45 pm and it’s still not turned off,” she told The Sydney Morning Herald and The Age.
Another Optus customer, Daniel, an anaesthetist, said he was on-call overnight for emergency operations and noticed the network was down about 3am.
“I was unable to make phone calls or use the internet,” he said.
Optus has not publicly confirmed whether landlines are affected.
Meanwhile, Melbourne’s entire suburban train network was brought to a halt on Wednesday morning due to a “communications outage”.
It is unclear whether the issue was related to the Optus outage. The city’s trains have since resumed but major delays are expected.
More to come