A suicide attack killed five people at the interior ministry in Baghdad on Monday as a key political bloc called for early elections in a worsening standoff that has stoked sectarian tensions.

The blast, which left dozens wounded, came just days after the capital was struck by its deadliest violence in more than four months and as US Vice President Joe Biden urged dialogue between Iraqi politicians to resolve their differences.

The parliamentary movement loyal to anti-US Shiite cleric Moqtada al-Sadr, meanwhile, said it backed the dissolution of parliament and early elections in a row that has seen Iraq's Sunni vice president accused of running a death squad and a deputy prime minister call the government a "dictatorship".

In Monday's attack, a suicide bomber rammed an explosives-packed car into the interior ministry compound when guards opened the main gates to allow electrical maintenance workers through, a ministry official said.

At least five people were killed and 39 wounded, security and health officials said, speaking on condition of anonymity. Among the casualties were at least two policemen killed and 14 wounded.

The blast came after a wave of attacks across Baghdad on Thursday killed 60 people, and violence in the provinces the same day claimed another seven lives. It was the deadliest day in Iraq since mid-August.

The spike in attacks comes with Iraq mired in political dispute.

On Monday, the political bloc loyal to Sadr called for the dissolution of parliament and early elections.

The movement's parliamentary chief Baha al-Araji said in a statement that his bloc in Iraq's Council of Representatives wanted to "dissolve parliament and repeat elections."

An official at the movement's headquarters in the southern holy city of Najaf said Araji's statement "represents all of the bloc, and it represents the opinion of the bloc."

The call comes after authorities issued an arrest warrant for Sunni Arab Vice President Tareq al-Hashemi on charges he ran a death squad, while Prime Minister Nuri al-Maliki has called for his Sunni deputy Saleh al-Mutlak to be sacked.

Hashemi denies the accusations, and Mutlak has decried the premier as a dictator "worse than Saddam Hussein".

The Sunni-backed Iraqiya bloc, to which both Hashemi and Mutlak belong, has boycotted the cabinet and parliament.

Hashemi, holed up at the official guesthouse of Iraqi President Jalal Talabani in the country's autonomous Kurdish region, told AFP in an interview on Sunday he would not go to Baghdad to stand trial and raised the prospect of fleeing Iraq.

Asked if he would return to Baghdad to face trial, Hashemi told AFP: "Of course not." The 69-year-old attributed his refusal to travel to the capital to poor security and politicisation of the justice system.

Turkish Foreign Minister Ahmet Davutoglu has said Ankara will not turn Hashemi away if he requests asylum, but that he should stay in Iraq.

"I have no intention to leave Iraq at this time, unless my personal security is endangered," Hashemi said in Sunday's interview. "Then, we will talk about this."

Biden, President Barack Obama's pointman on Iraq, has made a flurry of calls to Iraqi leaders this week, urging them to mend their fences.

In calls to Maliki on Sunday and Kurdish leader Massud Barzani on Saturday, Biden "exchanged views... on the current political climate in Iraq and reiterated our support for ongoing efforts to convene a dialogue among Iraqi political leaders," the White House said in a statement.