SA Health said a short time ago that it had been caught up in Optus’ nationwide service outage which occurred around 4am.

The outage has left millions of customers including South Australian government agencies, banks and businesses unable to make or receive phone calls or access mobile internet services.

Optus customers also can’t make emergency triple zero calls from landlines. Mobile triple zero calls still work.

SA Health said the outage is affecting its digital and phone services, although triple zero was still operating.

“Business continuity plans have been enacted across our hospitals and facilities while the outage continues,” the statement read.

“Safety is our priority and we ask people to please be patient as our doctors, nurses, allied health professionals and other staff attend to the sickest patients first.

“Most hospital numbers including switchboards are also impacted.”

Premier Peter Malinauskas said SA Police has “stood up” the State Emergency Centre (SEC) today and held two meetings on the outage.

He said the outage’s impact on SA Health had caused “substantial inconvenience, but not one that has had clinical implications on the ability of SA Health to look after its patients”.

“Critically, we have not seen any clinical implications as a result of the outage,” Malinauskas said at a midday press conference.

“All clinical services within SA Health remain ongoing and are able to be performed.

“Our emergency services and our emergency response – they are all operating as we would reasonably expect them to.”

Malinauskas said there was an issue with a mental health triage service which can’t receive calls.

Health Minister Chris Picton said the mental health triage service is seeking to switch networks as soon as possible.

SA Health’s electronic records system, Sunrise EMR, has not been affected, the Premier said.

“Patients who might be awaiting a test result could suffer a delay of receiving those test results, that is an inconvenience,” Malinauskas said.

“But where there is a critical need for a particular patient, that will be seen to and prioritised through alternative means of communication, even face to face if need be.”

Service SA is currently unable to take calls while SA Water customers can’t pay a bill over the phone, the Premier said.

Alert SA, a government service that notifies individuals about bushfire risk, has also been impacted.

Deputy Police Commissioner Linda Williams said: “This is particularly important as we head towards the end of the week when we can see some elevated fire danger ratings for some parts of the state.

“So we encourage people who would normally rely on Optus or Optus services as their main source of information to find alternates prior to that so that they are aware that they’re going to be in extreme fire danger areas so that they can activate their necessary precautionary plans for their safety and that of their families.”

SA’s public transport services are operating normally.

The Premier criticised Optus, saying they have had “very little communication” with the South Australian government.

“We are disappointed with Optus, they’ve let their customers down across the state, including the government,” Malinauskas said.

“Optus need to respond swiftly, communicate effectively with everybody about exactly what is going on here.

“There hasn’t been a great degree of communication coming out about this up until this point, which I think is disappointing.

“Telecommunications now is central to the functioning of the Australian economy, and it has a big impact on services across governments.

“And if Optus wants to see government as a customer then they need to be able to be a reliable service.”

BankSA and Commonwealth Bank also report that they are unable to receive calls.

The RAA has urged customers to call 8202 4600 if they need roadside assistance as their roadside assistance hotline is down.

Ramsay Health Care, which operates two clinics in Adelaide, also said its hospital phone services were down.

Optus said a short time ago that some of its services are being “gradually restored”.

“This may take a few hours for all services to recover, and different services may restore at different sites over that time,” Optus said on X.

“We reiterate our apology to customers for the nationwide service outage that has occurred this morning. We will continue to provide updates as we have information available.

“We are aware of some mobile phones are having issues connecting to 000. If Optus customers need to call emergency services, we suggest finding a family member or neighbour with an alternative device.”

Optus CEO Kelly Bayer Rosmarin told ABC Radio Sydney around 10am (Adelaide time) that the company did not yet know the cause of the outage.

She said engineers have spent hours trying to uncover the source of the outage and bring the system back online.

“The team has tried a number of paths of restoration,” she told the radio, calling in via Whatsapp.

“So far, we have not had the result we have hoped for and we’re pursuing every avenue to get everybody back online as soon as possible.”

Bayer Rosmarin said there was no indication the outage was the result of a cyber attack.

Asked if it was a software issue, Bayer Rosmarine said: “I mean, it’s highly unlikely.

“Our systems are actually very stable. We provide great coverage to our customers.

“This is a very, very rare occurrence and when I have more information about the root cause, I will be the first to let all our customers know.”

Asked how long she thought it would be until the system is restored, she said: “Well, we’re working really, really hard to get it up and running as soon as we possibly can.”

Optus is Australia’s second-largest telco with more than 10 million customers.

Federal Communications Minister Michelle Rowland said it was vital for Optus to be “transparent and timely” in informing its customers that it was working to urgently restore services.

She told reporters Optus customers were experiencing “a high level of anxiety and frustration at the moment” and deserved to get services restored promptly.

“What we do know is that this is a deep fault,” Rowland said.

“It has occurred deep within the network. It has wide ramifications across mobile, fixed, and broadband.”

Rowland said she had no information to confirm the outage was caused by a cyber attack.

She also urged business customers affected by the outage to “keep receipts” if they’ve been affected in case there is a potential for future compensation.

“It’s important especially for small businesses to keep receipts, so that any recourse and any redress that may be available to them has that evidentiary base,” Rowland said.

Melbourne train services were also interrupted early on Wednesday, reportedly due to the Optus outage.

All metropolitan services were stopped from about 4.30am due to a communications fault across the train network.

Metro Train services started to resume just before 6am but major delays continued throughout the morning peak as services were restored.

“We apologise to our passengers for the delay to their travel this morning,” Metro Trains chief executive Raymond O’Flaherty told AAP in a statement.

“We thank passengers for their patience while trains return to their normal timetable.”

Service NSW call centres and phone lines across Northern Health’s hospitals and virtual emergency department in Melbourne’s north were also down due to the Optus outage.

-With AAP and David Simmons