"The fake prime minister and his purported government have been thrown out of office by the judiciary", Sagala Ratnayake, a member of Wickremesinghe's United National Party, said.
Sri Lanka's toppled premier likened the president to Hitler on Tuesday as he demanded to be reinstated, nearly six weeks into a paralysing political crisis in the Indian Ocean nation.
Sirisena came to power in 2015 on a pledge to uphold democracy and stamp out corruption, but his popularity has been hit by a crisis many say he triggered because of personal differences with former Prime Minister Wickremesinghe. "He is an unsuitable politician for the country", he said.
However, Wickremesinghe's UNP claims that Sirisena will be left with no choice as he would be the man who will command the confidence in the House. However, vowing to resolve the crisis in "seven days", Mr. Sirisena told his supporters on Tuesday: "I have always taken decisions in the best interest of the country and the people".
President Maithripala Sirisena met with top bureaucrats on Tuesday and told them to "fulfill their respective duties and responsibilities" without disruption while the prime minister and cabinet were prevented by the court from carrying out their work.
The crisis deepened on Friday when parliament voted to halt payment of ministers' salaries - a move to pressure the disputed government of Rajapaksa.
Monday, appellate judge Preethipadhman Surasena issued the stay, laying groundwork for a full hearing by the court on December 12 to decide the matter.
A Sri Lanka court on Monday suspended Mahinda Rajapakse's powers as prime minister and ruled that his cabinet could not function until its legitimacy was established.
Meanwhile, the Supreme Court on Tuesday resumed hearing the case challenging Mr. Sirisena's decision to sack Parliament and hold snap polls, which petitioners argued were not within his rights before the current legislature completed four and a half years. "We are preparing papers to go to the Supreme Court first thing in the morning tomorrow".