However, the achievement was dulled by fresh drama in the central south-west communications exchange when ISDN service to more than 120 major business customers dropped off at 8am and took almost five hours to restore.

Businesses from Warrnambool through to Portland were left with blank or intermittent lines and again had to rely on mobile phones in the interim.

Technicians scrambled to repair equipment in the mainframe, which had been affected by soot and smoke from the fire.

Telstra spokesman James Howe said links to several business customers and rural communities would be rerouted through the South Melbourne exchange in the next few days. 

“There will be service interruptions for 10 minutes or so while the re-parenting switchover happens,” he said.

“We had a pretty significant failure in the morning, but all services are back up and running now.

“The fire had impacted the capacity of the Warrnambool mainframe to handle peak load. When we re-parent some services through South Melbourne it will reduce the load and reliance on a single point.”

Meanwhile, technicians used a giant crane yesterday to install new gear on the Warrnambool exchange mobile phone tower to increase data carrying capacity by 60 per cent.

“This upgrade had been planned to happen some time in the first half of next year, but because more people have been using their mobile phones during the outage and we had the technicians here we decided to install the equipment this week,” Mr Howe said.

Technicians who have worked around the clock in shifts to rebuild the damaged exchange will stay for the next few weeks to iron out crossed lines and numerous service faults.

“We encourage people to notify us of faults on the 1800 171 355 helpline and technicians will be despatched,” Mr Howe said.

“We expect there will be issues to resolve for a few weeks and we want to make sure the system is running properly.

“Our Warrnambool-specific call centre staff have been instructed to understand the needs of customers in this area and we are reminding other call centres of the issues also.”

He said about 30 compensation claims under $1000 had been processed and about 10 claims of more than $1000 had been lodged.

“We are aiming to turn them around quickly,” he said.

There is still no official explanation on the cause of the fire which broke out in a common room at the exchange about 4.30am on November 22, blacking out 65,000 landlines, 15,000 broadband services and more than 80 mobile phone towers.

The federal government parliamentary inquiry’s first public hearing will be in the Warrnambool Lighthouse Theatre on Monday from 10am to noon.

pcollins@fairfaxmedia.com.au