His submission came while a three-judge bench headed by Justice N.V. Ramana was hearing a batch of petitions challenging the restrictions when the government revoked Article 370 granting special status to Jammu and Kashmir.
Section 144 of the Criminal Procedure Code (CrPC) empowers the authority to issue an order to prohibit the assembly of four or more people in an area.
The curbs had been imposed on August 4, a day ahead of the Central government moving a resolution in Parliament to scrap special status of Jammu and Kashmir granted under Article 370.
Sibal, appearing on behalf of Congress leader Ghulam Nabi Azad, asked whether under Section 144 "one can direct that no one shall speak". He emphasised that everyone has the right to speak with his family members.
Stressing that false news has to be monitored, he said there was no explanation for blocking landlines, the internet and post-paid mobiles.
He also pointed out that postpaid subscribers have had to pay fixed charges for the month of August and September when they didn't use the phone.
"They (the administration) never thought of any of this and took a decision to impose 144 CrPC", he said, adding cross-border terrorism is not something new and has not started on August 4.
Sibal also highlighted that a large number of people of Kashmir are peace-loving and that there is a need to protect their fundamental rights. The administration should have taken preventive measures to ensure that children could go to school.
( With inputs from IANS )