IRAQI Shi’ite leader Grand Ayatollah Ali al-Sistani spoke out for a new, “effective” government yesterday, increasing pressure on Prime Minister Nouri al-Maliki.

Ayatollah Sistani’s comments at Friday prayers contained thinly veiled criticism that Mr Maliki, who has been in office since 2006, was to blame for the nation’s crisis over the military blitz led by Islamic State of Iraq and the Levant (Isis) forces.

While Mr Maliki’s State of Law bloc won most seats in parliament in Iraq’s April 30 election, he now faces opponents bolstered by criticism from Washington, which has previously backed him.

“It is necessary for the winning political blocs to start a dialogue that yields an effective government that enjoys broad national support, avoids past mistakes and opens new horizons toward a better future for all Iraqis,” said the grand ayatollah in a message delivered by his representative Ahmed al-Safi in the holy city of Karbala.

The Iranian-born religious leader lives in the holy city of Najaf south of Baghdad.

His call to arms last week prompted thousands of Shiites to volunteer to fight against Isis.

Mr Maliki’s Shiite-dominated government has long faced criticism for discriminating against Iraq’s Sunni and Kurdish populations, but it is his systematic marginalisation of the Sunnis that sparked recent violence in support of Isis.

The Sunni population that was once the backbone of the army has not resisted the Isis invasion.

The newly elected parliament must meet by June 30 to elect a speaker and a new president, who in turn will ask the leader of the largest bloc to form a new government.

With Iraq in turmoil, Mr Maliki’s rivals have mounted a campaign to force him out of office, with some angling for support from Western backers and Iran.

Erstwhile backer US President Barack Obama said on Thursday: “We’ve said publicly, whether he is prime minister or any other leader aspires to lead the country, that there has to be an agenda in which Sunni, Shi'ite and Kurd all feel that they have the opportunity to advance their interest through the political process.”

Fierce battles raged yesterday between government troops and their Isis-led opponents for the airport at Tal Afar and the Baiji oil refinery.