"Frustrating" just about sums up the vibe of the Friday afternoon thousands of Australia just had, although that still might be underselling it.

It's the word Rockhampton florist Danielle Hempseed chose to use when the ABC asked how she felt being in the grip of one of the biggest global IT outages ever.

Fridays are usually busy at her gift shop as people bustle in before heading off on their weekend adventures.

But she may as well have shut shop early.

"Having point of sales down, EFTPOS down, and emails down, it makes it really hard for us to operate," she said.

Before it reached our shores, tech problems were already popping up in the US and New Zealand.

The outage was later identified to have been caused by a "defect" in an update by cybersecurity company CrowdStrike.

A raft of companies and government agencies were affected, with telco providers, media websites, banks and airlines also experiencing disruptions.

Prime Minister Anthony Albanese was quick to announce there had been no impact to critical infrastructure, with triple-0 services operating uninterrupted.

Nevertheless, the consequences of the incident were not insignificant.

Big problems at the airport

Chaos filled Brisbane Airport on Friday night, where crowds of travellers were stuck wondering what was happening.

For US national Richard Swearingen, it meant further delays to an already long journey from San Francisco to Queensland to lay his mother-in-law to rest.

"[My wife]'s in a wheelchair so not so mobile and of course we got bags, so [we're] just joining the masses here," he said.

He was meant to collect a rental car and check into a motel in Mackay ahead of his mother-in-law's funeral.

"I'm not sure if I'm going to lose the deposit on that [car hire] and end up paying double," he said.

"It's over $1,000 to get another flight [even] if I could, so the next thing is [getting] a hotel and hope this is all resolved by the morning.

Footy fans Deborah and Damien Irvine were also swept up in the delays, unable to board their flight home to Townsville after visiting the Queensland capital for State of Origin on Wednesday.

Already dealt a blow by the Maroons' defeat earlier this week, the husband laughed and said "we can only hope the Cowboys get up".

Elsewhere, Jetstar passengers Lucas and Liz Gibson were due to fly to Sydney from south-east Queensland but were left unable to check in.

"The service desk staff can't help, computers are down, they don't know what's going on, they're just waiting and seeing," Mr Gibson said.

Mr Gibson said they feel helpless.

"Nothing you can do we just have to wait and see, maybe we have to go home and start again tomorrow," he said.

Adelaide Airport was reported to be operating as normal on Saturday morning, after Friday's global IT issues.

An airport spokesperson said there were some residual delays and cancellations, mainly impacting Jetstar passengers.

They said eight airline arrivals and departures had been cancelled, including an international flight due to land in Adelaide from Denpasar.

Customers are being urged to check flight information online.

Businesses bounce back

Some bottle shops and service stations in Brisbane remained closed on Saturday morning, but supermarkets in Queensland and New South Wales seem to have bounced back following the CrowdStrike outage.

In Australia's largest regional city, Newcastle, small businesses appear largely unaffected.

Like the rest of the country, some of the city's chain supermarkets like Coles and Woolworths had to shut early on Friday.

A Coles store in the Newcastle city centre was open for business, with some self-serve check-outs impacted, but cards and cash were being accepted at the till.

A nearby Liquorland, owned by the Coles Group, was closed for business due to the outage.

One of Newcastle's busiest cafe strips, Darby Street, was quieter than usual for a Saturday morning — mainly due to strong coastal winds and cold temperatures.

Three Monkeys barista Nic Williams said the outage had not impacted them at all.

"I was very happy to come into work to find no issues," he said.

"[Registers and coffee machines] all working perfect and normal."

Mr Williams said they have been less busy today, and customers have been checking if they can use a card to pay for their brunch.

Not all businesses were so lucky.

In South Australia, Hey George owner Omid Ahmad said the outage was "a big hit to the pocket" after turning away about 50 customers wanting meals and at least 100 ordering coffee.

"All of a sudden we lost all our EFTPOS system, couldn't use the tills, we tried calling around trying to get an electrician here.

"You've got to carry cash, you can't just trust the cards and banks because they'll let you down, as you can see."

Big hit in the regions

Access to emergency services was largely unaffected, but there were some reports of disruptions to internal systems in hospitals.

One regional NSW resident told the ABC his mother-in-law was in hospital for spinal surgery she had been waiting more than a year for when the outage hit.

He preferred not to use his name, but said hospital staff had initially been unable to confirm if the woman had come out of theatre, or her location in the facility.

"It's very distressing … we are just sitting on our hands at the moment," he said.

In regional towns like Horsham, the inability of the local service station to operate was a cause of concern.

"Everything was going smoothly, and it just closed down."

Local technicians needed

Griffith University cybersecurity expert David Tuffley said the regions may have fared better because of simpler computer networks.

"Metro areas are a more complex set-up — there are more computers in more complex networks, and I think that very complexity worked against it, because once it all started, this cascade reaction, it just seized everything up," Dr Tuffley said.

"In the regions, the networks are simpler, and I think they probably fared better for that reason.

"There are more sites, more users, more computers in a metro area.