Iraqi premier Nuri al-Maliki called for a national dialogue Sunday after President Jalal Talabani said his rivals lacked the votes to oust him, but opponents insisted their efforts had "just started."

Critics of the prime minister have for months accused him of monopolising decision-making, and a political crisis that began in December has worsened in recent weeks, with open calls from a raft of political parties to pull the plug on Maliki's national unity government.

But late on Saturday, Talabani said groups opposed to the premier lacked the 163 parliamentary votes required to sack him, after which Maliki called on political leaders to unite to rebuild the conflict-racked country.

"I take this opportunity to renew a call for all political partners to sit at the table for negotiations, and to be open to discuss all disagreements," the prime minister said in a statement.

"I am sure we will be able to overcome all challenges and difficulties that are in our way," he added, while also thanking Talabani for his "constructive" role.

On Saturday, Talabani's office issued a statement saying there was insufficient backing to pass a vote of no confidence against Maliki.

"Due to a lack of (support), the letter of his excellency the president of the republic, although its text was prepared, was not given to the parliament," the statement said.

It said more than 160 lawmakers had originally supported the motion to unseat Maliki and, by extension, his government.

They included members of the secular Sunni-backed Iraqiya bloc, the main Kurdish faction, and the movement loyal to powerful Shiite cleric Moqtada al-Sadr.

All three of those parties are members of Maliki's national unity government.

The statement added, however: "Later, 11 of the signed lawmakers informed the office of the presidency of the withdrawal of their signatures, while two others requested to suspend their signatures."

It did not provide details on who the lawmakers in question were, or what blocs they belonged to.

At least 163 votes are required to pass a motion of no confidence in the prime minister, according to Article 61 of Iraq's constitution.

A no-confidence motion can be put before parliament either by the president or by one fifth of the 325 members of parliament.

Despite Talabani's statement, the crisis appeared to be far from resolved.

"It just started," Sadr said when asked by a follower if the issue of withdrawing confidence from Maliki was over.

Haidar al-Mullah, a leading Iraqiya MP, told AFP that "we are working to end the dictatorship" and that the required votes could be secured "in half an hour" if needed.

There "were clear Iranian pressures" on the president and some MPs, Mullah added.

Iraqiya, the Kurdish alliance, and Sadr's bloc were meanwhile meeting in the Kurdish regional capital of Arbil for further talks.

"Those who met today insisted that they will continue their efforts and the steps to achieve their goal," a statement issued on the website of Kurdish regional president Massud Barzani said of the gathering.

The parties "will continue to call on parliamentary powers by legitimate means to face one-man rule... and to condemn pressures exerted on members of parliament."