The trial in absentia of Iraqi Vice President Tareq al-Hashemi was delayed a week on Thursday after his lawyers called for it to be held in a special court as his allies dismissed the case as politicised.

Hashemi, one of Iraq's top Sunni Arab officials, stands accused along with several of his bodyguards of running a death squad, but left Iraq weeks ago and is not expected to attend the trial.

Hours before the trial was due to open on Thursday, shootings and bombings erupted in the Harithiyah neighbourhood where the Central Criminal Court of Iraq (CCCI) is situated, although not in the immediate vicinity of the court compound.

An Iraqi soldier was killed in a shooting at 8:00 am (0500 GMT), while three roadside bombs wounded two police bomb disposal experts at around the same time, an interior ministry official said.

"The trial has been postponed until May 10," Higher Judicial Council spokesman Abdelsattar Bayraqdar said.

Lawyers for Hashemi called for the case to be held in a special court rather than the CCCI, and a judge is to consider their request before the case resumes in a week.

"For people such as presidents and prime ministers, throughout the history of Iraq, there have always been special courts to try them," said Muayad al-Izzi, one of Hashemi's eight defence lawyers.

Neither Hashemi nor any of his accused bodyguards were present at the court, an AFP journalist said.

Thursday's trial was to tackle the assassinations of two security officials and a lawyer, Bayraqdar said.

The charges against Hashemi were first levelled in December after US troops completed their pullout, sparking a political crisis that saw the vice president's bloc boycott cabinet and parliament over accusations Prime Minister Nuri al-Maliki was monopolising power.

Hashemi and his political allies have slammed the charges as targeting their Iraqiya bloc, which won the most seats in March 2010 parliamentary elections but was outmanoeuvred for the premiership by Maliki's alliance.

"The judiciary is politicised," Iyad Allawi, a secular Shiite who is leader of the mostly Sunni-backed Iraqiya bloc, told AFP in an interview from the Kurdish city of Sulaimaniyah.

"There is plenty of evidence of this, not only related to Tareq al-Hashemi, but to previous cases in the judiciary. We do not believe a fair trial will be carried out."

Allawi added that a section of the judiciary was "absent, incomplete and not balanced," but did not elaborate further, only saying the Iraqi judiciary "must be reviewed".

Hashemi and some of his guards were on Monday also charged with killing six judges, and Bayraqdar put the overall number of accusations against the group at about 150.

Bayraqdar, who said further charges could still be filed, did not provide a breakdown of the accusations, or say how many Hashemi himself faces.

He said around 13 of Hashemi's guards had been released for lack of evidence, leaving 73 others.

After the initial charges were filed, the vice president fled to the autonomous Kurdistan region in north Iraq, whose authorities declined to hand him over to the central government.

They then allowed him to leave on a tour of the region that has taken Hashemi to Qatar, Saudi Arabia and now Turkey.