More followers of an influential Iraqi Shiite cleric have joined a rally in central Baghdad to press lawmakers to vote on a Cabinet shakeup proposed by the prime minister.

Police have cordoned off a downtown square with razor wire and concrete blocks after hundreds of Muqtada al-Sadr's supporters on Sunday erected camping tents for what's expected to be a long sit-in.

Al-Sadr on Saturday issued an ultimatum to parliament to vote on a new government on Monday's session.

Prime Minister Haider al-Abadi has offered a list of technocrats nominated for his new government but political blocs have rejected the nominees.

A vote on a second list was delayed last week when lawmakers staged a sit-in demanding the country's top political leadership step down, including al-Abadi and the parliament speaker.