The city has been battered by the heaviest rainfall in close to a century.
"Landline calls in the Chennai circle are free for a week. The phones whose dues are not paid will not be disconnected for 15 days," Prasad told reporters here.
The state-owned BSNL has also announced that it will allow free local and STD calls to other BSNL mobile phone users as well as 100 MB data for seven days for its pre-paid users.