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 in New Delhi.
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.
Other private operators are not behind, which are offering free talktime to their customers.
Airtel, whose services have been impacted in certain areas due to power failures by the unprecedented rains and floods, said it will offer talk time credit upto Rs. 30 for its prepaid mobile customers. It will also provide 50MB mobile data free with a validity of 2 days to prepaid customers.
It added that postpaid and fixed line customers, whose bills are due to be paid immediately, will get an extended time to make the payment.
"The uninterrupted rains have resulted in excessive water logging and disruption of essential services in Chennai, thus causing power failures and impacting our services in some regions. We at Airtel are working with local authorities to enable smooth mobile communication for Airtel customers across the city," it added.
As of September 30, Tamil Nadu (which includes Chennai region) had 82.06 million telephone subscribers.
Vodafone said it is offering a credit of Rs. 10 and 10 minutes of Vodafone to Vodafone calling to all pre-paid customers as well as 100MB of free mobile data.
Similarly, RCom is offering 10 minutes of all-India free calling and 50MB of mobile data free.
Aircel will offer free 10 minutes Aircel to Aircel calls across India to all its Chennai customers for the next three days. Apart from credit of Rs. 30, the operator will also provide 10 free all India SMSes and 100MB 2G/ 3G free mobile data valid for 3 days.