Citing 'public security', President Maithripala Sirisena issued a special gazette notification to give the police and the military powers to arrest and interrogate suspects without court orders.
Some 5,000 government troops and police are also listed as missing since the end of the insurgency.
Over 250 people, including 44 foreigners 10 of whom were Indians, were killed and 500 others injured in the blasts in three churches and as many hotels on April 21.
Sirisena on Monday also set up a new military command aimed at countering the threat from Jihadists and extremists in the aftermath of the Easter Sunday attacks.
Jayasundara has steadfastly refused to heed Sirisena's call to resign following April 21 coordinated blasts on three churches and three luxury hotels.
For a country in the midst of a general election, it would be instructive to learn from the experience of a neighbour that is struggling with a dysfunctional government.
Sirisena said he was using emergency powers to ban any form of face covering in public. The restriction will take effect from Monday.
Arguments have arised thast lack of communication and rivalry between President Maithripala Sirisena and Prime Minister Ranil Wickremesinghe has led to the blasts.
Zahran Hashim appeared in a video released by the ISIS group after they claimed the bombings, but his whereabouts after the blasts was not immediately clear.
There was no immediate claim of responsibility, but police on Monday arrested 24 people and declined to give further details.
For a day’s visit, he reached Tirupati, on Tuesday morning, and was received at the airport by Collector PS Pradyumna and Sub-Collector Mahesh Kumar and others.
At the end of the military conflict 10 years ago, some 84,675 acres of Tamil civilian land were under the military control.
The TNA and JVP put up a broad front to force Sirisena backtrack through court action.
The statement stands in contrast with President Sirisena's comments on Wednesday that he would send his own team to the UNHRC session later this month to seek a reprieve.
Sirisena felt that the execution of drug convicts is necessary w.r.t the fast-spreading drug menace in the island nation.