The Optus network outage has left some Hunter businesses reeling as their digital payment systems fail.
Rob Moore, who opened men's clothes store The Rake this week off the Hunter Street Mall, said he had lost the ability to take Eftpos payments.
"Good timing," he said on Wednesday morning, about seven hours after the Optus network went down.
"I have an Optus business account across a couple of businesses.
"My other business is in Sydney, so I can't communicate with them at the moment.
"Here in the store in Newcastle I've got my Eftpos machine running through an Optus sim card, so I can't process any sales."
Mr Moore said larger business would be suffering more.
"Hopefully it's going to be back up and running and it will be minimal impact for me, but I'm sure there are bigger businesses that are operating at a faster pace and a higher volume that are significantly impacted."
The nearby Mr Sister coffee shop was taking only cash sales.
Staff said the lack of a digital ordering system was making life harder for the baristas.
Darby Street cafe owner Anthony Strachan said that thanks to a "rare moment of foresight" he was able to use a back-up Eftpos machine linked to wi-fi at his Three Monkeys store.
"I've had a few people coming in saying they couldn't pay at other cafes," he said.
Customers were working on laptops in the Autumn Rooms cafe next door because their Optus service had failed at home.
Hunter Business chief executive Bob Hawes said many businesses across Australia had been affected.
"Unless they've got a fallback like another sim card or a second provider in their back pocket, which many people wouldn't have, they're going to be affected," he said.
"Given the swing-over to a non-cash economy we've experienced, they're going to be in a bit of a tight spot until it's back up and going.
"Bigger businesses which have all their telecommunications systems aligned to Optus would be struggling as well."
Optus services started coming back online during the afternoon.
