The president of Iraqi Kurdistan travelled to Baghdad on Wednesday for talks with senior officials just hours ahead of a special parliament session to discuss weeks of deadly anti-government demonstrations.

The head of the United Nations' mission in Iraq (UNAMI) was expected to attend the legislative meeting in the afternoon as diplomatic pressure on Baghdad intensifies.

Protests demanding a new leadership have rocked Iraq's capital and Shiite-majority south for weeks, the demonstrators undeterred by government pledges of reform or the deaths of more than 300 people.

On Wednesday morning, the president of Iraq's autonomous Kurdish region (KRI) Nechirvan Barzani met with Prime Minister Adel Abdel Mahdi in Baghdad.

The two leaders are believed to have good personal ties, and the KRI capital Arbil has backed the current government.

Barzani was also scheduled to meet President Barham Saleh and Speaker Mohammed Halbussi, who will chair an afternoon parliament session attended by UNAMI chief Jeanine Hennis-Plasschaert.

She will address the main political blocs and brief lawmakers on her recent meeting with the country's top Shia religious authority Grand Ayatollah Ali Sistani.

Sistani has backed a UN roadmap out of the crisis, which includes electoral reforms and anti-graft measures within two weeks, followed by constitutional amendments and legislation on infrastructure within three months.

The 89-year-old cleric said protesters "cannot go home without sufficient reforms" but also voiced fears that authorities were "not serious" about enacting them.

Bolstered by his comments, anti-regime demonstrators have returned to the streets after a crackdown by security forces had temporarily reduced the turnout at rallies.

Activists clashed with riot police in Baghdad on Wednesday near the main protest camp of Tahrir (Liberation) Square, AFP's correspondent said.

In the port city of Basra, some 800 students and teachers returned to camp outside the provincial headquarters after they had been cleared out over the weekend by riot police.