The issue which began last night is causing difficulties with making and receiving phone calls.

The problem has been ongoing since last night and still needs to be resolved.

However, Telstra assures its customers that calls to Triple-Zero and mobile data are unaffected.

According to the real-time tech intelligence network Downdetector, reports began 10pm.

The telecommunications company is actively working to resolve the issue and has advised its customers to try using Wi-Fi calling or other apps like FaceTime if they encounter problems.

“We’re sorry for the late-night hassle for our customers,” an update on its website read.

Customers, in particular business owners, are beginning to vent their frustrations with the telco directly on its social media feeds.

“Trying to run a business here – no phone,” one customer wrote directly to the company’s Twitter page.

“Cheers Telstra, running a business and the phone won’t take calls or make them,” another wrote.

“Wow Telstra – hope no one tries to call me for a job,” wrote another.

More to come …