Iraqi Prime Minister Haider al-Abadi has accepted the resignation of another minister, his office said on Wednesday, as he seeks to move forward with long-stalled efforts to replace the cabinet.

Abadi agreed "to accept the resignation of Minister of Higher Education Hussein al-Shahristani," his office said in a statement, referring to a long-serving official who has also held positions including deputy prime minister and oil minister.

The statement came a day after the premier's office announced he had accepted five more ministerial resignations, as well as that of the interior minister earlier this month.

But replacing the ministers will likely be a significant challenge, as Abadi has struggled to win parliament's approval for new ministers he has proposed.

Lawmakers finally approved a few of Abadi's candidates in late April, but a court later scrapped the session, from which some MPs were barred from attending.

The premier called in February for the cabinet to include technocrats, but has faced major opposition from powerful political parties that rely on control of ministries for patronage and funds.

Populist Shiite cleric Moqtada al-Sadr later took up the call for a technocratic government, and has organised repeated demonstrations calling for reforms.

His supporters have broken into Baghdad's fortified Green Zone area, where the government is headquartered, on multiple occasions during Friday protests.