The outage in Peterborough, on the Great Ocean Road in Victoria, has left many of the town's older residents cut off and isolated just as spiking COVID cases have begun affecting other critical services and made it riskier to venture outdoors.

Peterborough Licensed Grocers owner Kathy Burl said the situation was "just ridiculous" and it wasn't the first time the connection had crashed.

"It's been happening repeatedly for at least a year. It feels like there's not much you can do about it," she said.

But at five days the current outage was the longest so far.

By the time it's due to be be fixed, businesses and local residents will have been disconnected for almost two weeks.

Ms Burl has had to divert the shop phone to her mobile so customers can get through. Fortunately the EFTPOS connection uses a SIM card, but there's no backup if mobile coverage - which is currently still working - happens to go down.

"There are plenty of elderly people who don't have mobile phones, so it's very hard for them," Ms Burl said.

A Telstra spokesperson confirmed the outage, seeking to minimise the significance of the issue.

"We're aware of an issue impacting a small number of home phone services in Peterborough," he said.

The spokesperson didn't address the internet blackout, only saying nbn services were "working as normal".

A significant section of Peterborough isn't connected to the nbn network with local resident Michael Moore saying he hadn't had internet connection for almost a week.

"On top of the phone outage, our business has really been affected by the internet being down," he said.

The Telstra spokesperson said it "believes the issue is related to a hardware fault in a remote unit and technicians are investigating".

Ms Burl said the circuit had blown at the main exchange, but had been told there were no plans to upgrade the unit despite ongoing problems.

"Apparently they're just going to repair it," she said.

"It will just happen again."

The Standard asked Telstra why the unit was being repaired, rather than upgraded, but it declined to respond.

Ms Burl said the phones at the Peterborough CFA building were also down, which was particularly worrying with warm, windy weather on the way.

"The emergency response is a problem," she said.

Peterborough CFA captain Steve Beaton said he was investigating the issue.

It remained unclear why the outage would take nearly two weeks to fix. The Standard asked Telstra about the delay, but the spokesperson only said the company was "working as quickly as we can to repair the issue".

"We know these sorts of impacts can be frustrating but customers can continue to use their mobile services to stay in touch," the spokesperson said.