More than 250 people died in the blasts targeting worshippers in three churches and in three luxury hotels.
"(President Maithripala Sirisena) has made this decision to strengthen national security as well as to not inconvenience any demographic group so as to create a peaceful and harmonious society in Sri Lanka", said the presidential statement, which was released Sunday.
In a later statement, the group identified the seven suicide bombers by their noms de guerre (false name).
Police say they have arrested over 150 people suspected of links to jihadists who carried out the bombings.
It comes as President Sirisena said he was using emergency powers to bring in the ban "to ensure national security" following the Easter attacks that killed more than 250 civilians. What are your thoughts on this?
Sri Lanka remains on high alert in the wake of the coordinated strikes.
Sri Lanka Prime Minister Ranil Wickremesinghe has assured the Christian minorities of protection and security, while expressing deep anguish and disappointment over failing to intercept the terror attack on April 21.
Some security measures are steadily being relaxed, with a social media ban in the country being lifted.
In a late night order on Sunday, the Sri Lankan government banned all face covers, including Islamic veil burqa, which hinders facial identification of a person.
According to news outlet India Today, the All Ceylon Jamiyyathul Ulama, an organisation of Muslim clerics in Sri Lanka, had also asked women to avoid wearing face coverings.
The blasts left 253 people dead and hundreds more injured.
"We pray that in this country there will be peace and coexistence and understanding each other without division", he said.
"This is a time questions such as, does God truly love us, does he have compassion towards us, can arise in human hearts".
The Islamic group's media network published a video on Monday purporting to come from al-Baghdadi, in which he said the Sri Lanka bombings were Islamic State's response to losses in its last stronghold of Baghouz in Syria.
Sirisena added that analysis of explosives and devices retrieved by authorities suggests the bombs used in the attacks were manufactured locally.