Under pressure from the local as well as worldwide organizations including the United Nations, European Union and Western governments, the President chose to reconvene the parliament on November 14, just two days ahead of the scheduled date.
New elections are likely to be held in early January, almost two years earlier than originally planned, a government minister told the AFP news agency.
Sirisena announced on Friday night that he was dissolving parliament and called fresh elections on January 5, two weeks after sacking prime minister Ranil Wickremesinghe and replacing him with the controversial Mahinda Rajapakse.
Dinesh Gunawardena, a government minister from Sirisena's party alleged that parliament was dissolved because of the conduct of Speaker Karu Jayasuriya.
Given those views, it was not immediately clear how Sirisena can legally dissolve parliament, though his legal experts have said there are provisions for him to do so.
The deposed leader, who has remained holed up in the prime ministerial residence since his abrupt dismissal on October 26, has demanded a parliamentary vote to prove his majority. "At the end of the day, he is a victim of his own homegrown crisis". He refused to acknowledge any human rights abuses in the final campaign, in which rights groups say up to 40,000 civilians died.
The United States voiced concern on Saturday after Sri Lanka's president ordered snap elections, as lawmakers warned that U.S. aid was in question.
"This is a gross violation of the constitution", Harsha De Silva, a lawmaker in Wickremesinghe's party, told Reuters in reference to the dissolution of parliament.
"The party will be pursuing the intervention of the courts to ensure the rule of law and the Constitution is protected against autocratic moves", a UNP statement said.
"We will demonstrate to the public of Sri Lanka our majority".
"As a friend of Sri Lanka, the United Kingdom calls on all parties to uphold the constitution and respect democratic institutions and processes", Field said.
Earlier, U.S. Rep. Eliot Engel, the top-ranking Democrat on the House Foreign Affairs Committee, and two other lawmakers wrote to Sirisena warning that actions circumventing the democratic process could impact U.S. assistance - including a planned five-year aid package from the Millennium Challenge Corporation worth hundreds of millions of dollars.
Sirisena sparked the two week-old drama last month by sacking Ranil Wickremesinghe as prime minister and naming Mahinda Rajapaksa - the country's authoritarian president from 2005 until 2015 - as his replacement.
"Unfortunately, we fear that recent actions, if not corrected, will threaten your country's democratic development and derail the progress made in recent years", said the letter to Sirisena.