Optus customers have been hit with mobile phone and internet outages on Friday, with the telco working throughout the morning to try and fix the problem.

An Optus spokesperson said the company had been working to restore services after the issues began from about 10am.

Hundreds of customers in Victoria, NSW, Queensland and the ACT took to social media to complain.

Many said they could not connect to the internet and were unable to make calls, with reception cutting in and out.

Optus advised customers via Twitter that it had "identified a fault", was aware of an issue affecting mobile services and was attempting to fix it as soon as possible.