Iraq's prime minister has accused the international coalition fighting Islamic State (IS) of not doing enough to tackle the group and said important members such as Saudi Arabia are not curbing the flow of foreign fighters to his country.

Western and Middle Eastern countries in the coalition are meeting this week in Paris. Part of their agenda is to persuade the Iraqi government to repair its relationship with Iraq's Sunni minority.

The meeting follows the Iraqi government's biggest military setback in nearly a year. On May 17, IS seized Ramadi from the weakened Iraqi army. The capital of the overwhelmingly Sunni Anbar province is just 55 miles west of Baghdad.

Since then, government troops and Shi'ite militias have been building up positions around the city. Many of Iraq's minority Sunnis dislike hardline Sunni IS but also fear the Shi'ite militias after years of bloody sectarian strife.

Prime Minister Haider al-Abadi, a moderate Shi'ite, can only persuade Sunni tribes to fight IS if he demonstrates he can control the powerful Shi'ite militias whose military muscle he now depends on.

He said he was confident the appeal to the Sunni tribes was "on track" and rejected suggestions Iraq was not doing enough politically.

"To be honest, we need a lot of political work on the part of the coalition countries. We need an explanation why there are so many terrorists from Saudi Arabia, the Gulf, Egypt ... European countries. If it is due to the political situation in Iraq, why are Americans, French and German (fighters) in Iraq?" he said.