Telstra area general manager Bill Mundy said there were complications during planned works, attempting to migrate 13 ADSL modules to a different platform. 

"During this migration three of the modules failed and affected 723 ADSL customers in the Warrnambool area," he said.

"The issue was resolved and all services restored at 11:54am.

"We thank customers for their patience and again apologise for the inconvenience caused."

According to a Kelp Street customer Jenny Fawcett, Telstra informed residents the service would be interrupted for six hours starting at midnight on Wednesday morning.

The Deakin University student said the outage came at the worst time as many prepared for exams at the end of the trimester.

"We pay a whopping big price for the internet so we can study and not having internet today is a major problem," she said.

"Telstra must know Warrnambool is a university town.

"There are so many with exams study or people researching for assignments - it's the biggest week of university and they decide to fix the internet that doesn't have a problem.

"It's not good enough and they won't tell us what problem is, but you don't have time to switch to another provider.

"As a rural town we rely on Telstra because we don't have the options available in the city."

j.pech@fairfaxmedia.com.au