The areas worst affected by the Queensland floods may have further problems, with mobile service outages possible if battery backups fail later today.
Mains power was cut early this morning, forcing some mobile towers to fail over to eight-hour battery backups. Some remain inaccessible, meaning Telstra technicians cannot replace their batteries.
Telstra is manning some of the most critical towers in the Brisbane CBD, and has deployed generators that can maintain power for up to five days.
If services fail, the telco may be able to reroute traffic between its functional network towers to ensure services continue.
But the network is already heavily stretched and has suffered a four-fold increase in the number of service outages.
"We've got battery backup so we're not experiencing issues. That could change in eight hours when those run down," Telstra said.
"We will replace batteries and generators as we can. Obviously we can't get into some areas due to submerged roads and that will stay the same possibly for several weeks. It's going to take a long time to recover.
"Our biggest issue is mains power."
The telco is unsure what regions may have services cut because the floods have not yet peaked and conditions are changing.
In the interim, technicians are on rotation, and are replacing batteries that can still be accessed. They have also built rudimentary reinforcements to protect valuable exchanges from flooding and some technicians are even sleeping within the exchanges.
Of Telstra's three critical exchanges, its Wollaston and Charlotte street facilities are considered safe, but a third at Edison Street is at risk because it lies in a basement.
Optus is experiencing the same issues, with some areas of the mobile and fixed Optus networks affected as of 1pm today.
"As the flooding situation is changing rapidly, an increasing number of mobile sites as well as fixed network nodes are at risk due to power outages which may disrupt fixed and mobile services to customers," the company said in a statement. As with Telstra, Optus was trying to deploy backup generators where possible.
Optus expected some disruption of 2G, 3G and business internet services in the Brisbane CBD later today because of the power outage. With network capacity prioritised for voice, mobile internet will also be slow. Several hybrid-fibre coaxial nodes have been impacted in Ipswich, affecting home phone and internet services to some customers.
In Toowoomba and surrounds, two mobile towers are currently without power, although there is still limited coverage being supplied by alternate towers. The mobile towers in the Lockyer Valley ran out of battery power at 9:10pm last night, cutting off all mobile services. This morning, the telco deployed power generators to partially restore services at five mobile sites.
One of Optus' Sydney-to-Brisbane fibre links has also been cut due to the floods. Services have been switched to an alternate link.
Floods have also been affecting Vodafone services. Two transmission facilities in Grantham and Withcott have experienced outages and are expected to have operations restored this afternoon. Other areas are expected to lose voice and data services due to power outages if the situation deteriorates.
The floods have also disrupted the National Relay Service, which provides telecommunications services to deaf and hearing- or speech-impaired people. Emergency services are still operating. The service was scheduled to evacuate its main call centre in Brisbane today.
Australian Communications and Media Authority chairman Chris Chapman said that his organisation was working with the service to find a dry location to host its backup server.