Four Iraqi political parties say they have formed an alliance in an effort to break the deadlock which has severely weakened the Shia-led unity government.
The new alliance will enable delayed legislation to be passed
The Moderates Bloc of Shia and Kurdish politicians was announced by PM Nouri Maliki and President Jalal Talabani.
The main Sunni Arab party - the Iraqi Islamic Party - declined to join.
With almost no Sunni Arab ministers in the cabinet, correspondents say it may be an attempt to dispel the impression the government is close to collapse.
The BBC's Middle East analyst Roger Hardy says, on the face of it, the new alliance is a puzzling move.
For days, the Iraqi government has been struggling to arrange a summit of leaders of the main political factions. However, these efforts have so far come to nothing.
Instead the four dominant parties in the government - the Daawa Party, the Supreme Islamic Council of Iraq, the Patriotic Union of Kurdistan and the Kurdistan Democratic Party - have announced what they are calling a new Moderates Bloc (Kutla al-Mutadilin).
Speaking in Baghdad, the leaders said the alliance would provide a majority in parliament that would allow delayed legislation to be passed - including measures demanded by the US.
Mr Maliki said: "The political process is suffering from a deadlock... [which] is absolutely unacceptable to the forces which struggled and worked very hard to build a new Iraq based on democracy, freedom, justice and equality.
"This agreement has come about to move the political process out of this deadlock."
Mr Talabani stressed the four parties had not broken off from the United Iraqi Alliance or the Kurdistan Alliance.
"It is an accord among these four parties that adhere to their previous alliances and that continue to work within these alliances," he said.
Mr Talabani said he would welcome the Iraqi Islamic Party reconsidering its decision not to join the alliance.
However, leader of the party, Vice-President Tariq Hashemi, told the BBC that the current political situation was "not conducive to creating new political blocs".
"There are many differences over how to manage the security situation and deal with those in power committing flagrant human rights violations. They can't be deemed moderates," he said.
"The government's performance vis-a-vis human rights must be improved."
In recent weeks almost all Sunni members of the cabinet have quit. Others are boycotting meetings, leaving at least 17 cabinet seats empty.
Mahmoud Othman, a prominent Kurdish politician, says the new alliance would try to fill the vacant posts.
He said the idea of holding a summit was still alive, but said that drawing in the Sunnis - who have denounced a government they say is indifferent to their demands - would be difficult.
Solving the problem needs the help of the neighbours, Mr Othman told the BBC, as the Iraqis on their own may not be able to do it.