Sirisena issued orders to extend the Emergency for another month from Friday midnight, according to a gazette notification.
According to the notification, the Emergency was in effect for public security, preservation of public order and maintenance of supplies and services essential to the life of the countrymen, the Colombo Page reported.
The President had declared the Emergency on April 22, a day after attacks on three churches, three luxury hotels and two other locations. The bombings were claimed by the Islamic State terror group.
Earier on May 22, Sirisena extended the Emergency by a month as security forces continued nationwide raids to hunt down suspects linked to the attacks. He had assured the diplomatic community in Sri Lanka then that it would not be extended.
Sri Lanka's police and military have arrested over 100 suspects in the crackdown.
The need to extend Emergency regulations has been questioned by some political leaders and activists in the island country, with the Tamil National Alliance voting against the motion when it was presented in Parliament in May.
"We don't think it's necessary to have emergency regulations in place now," TNA Parliamentarian M.A. Sumanthiran told Efe news.
"The regulations are far reaching and draconian in nature. Also, two cases being heard on the regulations in courts. We will be voting against the motion this time as well," he said.
The Sri Lankan government has initiated several investigations into the Easter Sunday blasts, including by a presidential committee and a parliamentary select committee. The House panel announced on Saturday that both Prime Minister Ranil Wickremesinghe and two former law and order Ministers would meet it to give evidence.
The Acting Inspector General of Police ordered on Friday a criminal investigation into lapses by nine top police officers with regard to bombings. Sri Lankan authorities blame local extremist groups National Thowheed Jamaath (NTJ) and Jammiyathul Millathu Ibrahim for the attacks.
The country's Criminal Investigation Department also brought five suspects, arrested in Dubai in connection with the attacks, to the island earlier this month and are being questioned.
The bombings also caused significant damage to Sri Lanka's tourism sector.
( With inputs from IANS )