THE Far North was thrown into a telecommunications dark age yesterday when the Optus network crashed across Queensland.

About 8am yesterday, a fibre-optic cable was cut by an excavator on the Gold Coast, severing phone, internet, email, fax and mobile coverage.

Optus director of network operations Peter Sutherland said earlier problems had knocked out back-up systems.

While services were restored about four hours later, many Optus clients were left seething.

"We apologise to our customers for the inconvenience this has caused them," Mr Sutherland said.

At a press conference, Queensland Premier Anna Bligh said the disruption to services was "unacceptable".

Federal Communications Minister Stephen Conroy said the incident was under investigation.

During the chaos, Innisfail and Mareeba hospitals were not able to receive or make calls and were only contactable by emergency mobile phone numbers.

Cairns Base Hospital as well as Tully, Babinda, Gordonvale, Mossman and Atherton hospitals were not able to make outgoing calls.

Some flights at Cairns airport were delayed because check-in and boarding systems also failed.

Cairns police Sen-Constable Cary Coolican said the system blackout only affected long distance calls with the station able to receive all calls from non-Optus phones.

The outage also posed problems for the Queensland Ambulance Service and Queensland Fire and Rescue Service. The Cairns coast guard attempted to receive three calls mid-morning but had a dead line each time the phone was answered.

Louise Hare’s business was one of many across the state to be affected by the system blackout.

Besides not being able to use her phone, the gem store owner said she could only make cash transactions in the morning as her Eftpos machine was not working for at least an hour.

"It could have been bad if someone wanted to spend $2000," she said.

Share this article