The decision, announced by his office, would eliminate four ministries, including those of human rights and women's affairs, and consolidate others.
The move follows a far-reaching reform plan approved by parliament last week that eliminated the country's three vice presidencies and three deputy prime ministers, as well as reducing the budget for the personal bodyguards of senior officials and transferring it to the interior and defense ministries.
Iraq's top Shiite cleric, Grand Ayatollah Ali al-Sistani, has lent his support to demands for reform, and parliament unanimously approved the wider reform plan last week in a dramatic show of unity for a country riven with sectarian and political rivalries.
Those reforms dismantled much of the top-heavy government erected in the years after the 2003 U.S.-led invasion that toppled Saddam Hussein. The three vice presidencies were intended to give equal representation to the country's Shiite majority and Sunni and Kurdish minorities.
IS militants attacked Iraqi troops Sunday outside the militant-held city of Fallujah, killing at least 17 troops, officials said.
Four suicide attackers drove explosives-laden military vehicles into government barricades outside Fallujah, west of Baghdad, setting off heavy clashes, a police officer and an army officer said. The officials said 15 other troops were wounded.
Both officers spoke on condition of anonymity as they were not authorized to release information.
