Sunni Vice President Tareq al-Hashemi has been charged with running a death squad while Prime Minister Nuri al-Maliki has threatened to dissolve power-sharing and called for Sunni deputy premier Saleh al-Mutlak to be sacked.
Mutlak and Hashemi's Sunni-backed Iraqiya party has boycotted parliament and the cabinet, while Washington has urged dialogue among the country's political leaders.
"Iraqiya thinks all the choices are still available, and among them are holding new elections," the bloc said in a statement, adding that another option was Maliki's pan-Shiite National Alliance nominating a replacement for the premier.
The calls echo those of Barzani and the Sadrist bloc, both of whom control multiple ministries in the power-sharing government.
Barzani told Al-Jazeera in an interview televised on Tuesday that he had "called for an urgent meeting of political leaders. ... If the meeting fails, we have to go for early elections."
The Kurdish leader last year hosted key talks that ended nine months of protracted negotiations to lay the foundations for Iraq's power-sharing government.
Baha al-Araji, the leader of the Sadrist parliamentary bloc, said on Monday that the movement supported the dissolution of parliament and early elections.
Iraq's March 2010 elections resulted in Iraqiya winning the most seats but falling short of an absolute majority. After the polls, Maliki formed a larger coalition and took the lead of the unity government.
Three senior Iraqiya leaders on Wednesday accused Maliki of trying to assemble a new dictatorship that risked plunging the country into civil war now that American troops have withdrawn.
In an op-ed published in the New York Times, Iraqiya leader Iyad Allawi, parliament speaker Osama al-Nujaifi and Finance Minister Rafa al-Essawi accused Maliki, a religious Shiite, of using security forces and the judiciary to hound his mainly Sunni opponents.
"The prize, for which so many American soldiers believed they were fighting, was a functioning democratic and nonsectarian state," they wrote.
"But Iraq is now moving in the opposite direction -- toward a sectarian autocracy that carries with it the threat of devastating civil war."
The support of Iraqiya, which garnered most of its seats in Sunni areas, is seen as vital to preventing a resurgence of violence. The Sunni Arab minority dominated Saddam Hussein's regime and was the bedrock of the anti-US insurgency after the 2003 invasion.