The Iraqi parliament voted on Tuesday to oppose an independence referendum planned by Iraqi Kurdish leaders for later this month prompting a walkout by Kurdish lawmakers.

Speaker Salim al-Juburi, a Sunni Arab, said the vote required the government to "take all steps to protect the unity of Iraq and open a serious dialogue" with Iraqi Kurdish leaders.

Prime Minister Haider al-Abadi and other top officials have said repeatedly that the referendum planned for September 25 would violate Iraq's constitution.

Kurdish leaders plan to hold the plebiscite not only in the three northern provinces where they have long enjoyed autonomy but also in other historically Kurdish-majority areas of Iraq that Kurdish forces captured during the battle against the Islamic State group. 

Tuesday's vote in the federal parliament was held after 80 lawmakers asked for the issue to be added to the day's agenda.

The planned referendum is non-binding but has been criticised by Iraq's Western allies as a distraction from the war against IS.

It has drawn stronger opposition from powerful neighbours Iran and Turkey who fear that it will stoke separatist sentiment among their own large Kurish minorities.