The country's capital and Shiite-majority south have been rocked by demonstrations since October demanding an end to corruption and a total overhaul of the ruling class.

Allawi, a two-time communications minister, has until March 2 to propose ministers to parliament, which must grant them a vote of confidence.

Iraqi officials have quietly expressed scepticism he would be able to complete it in time but Allawi surprisingly announced he would submit the lineup early.

"We're nearing a historic achievement: completing an independent cabinet of competent and impartial people, without the intervention of any political party," Allawi said on Twitter.

He pledged to "submit the names of these ministers within the current week", which begins on Sunday in Iraq.

"We hope members of the parliament will respond and vote on them in order to start implementing the people's demands."

Parliament is due to be in recess until mid-March and the speaker, Mohammed Halbusi, has not scheduled an extraordinary session.

Allawi was nominated on February 1 as a consensus candidate among Iraq's fractured political parties but has only been publicly endorsed by Sadr, who has a cult-like following across the country.

The cleric first backed the rallies but split with the main protest movement after endorsing Allawi, whom demonstrators consider too close to the political elite that has governed Iraq since the 2003 US-led invasion.

Since then, cabinets have been formed through sectarian power-sharing, which lends itself to widespread horsetrading among various sects and parties.

The country's Shiite, Sunni and Kurdish factions are likely to hold on tight to their shares of the current cabinet and hope to carry them over into the next cabinet.