Kuwait will host an international conference in February on the reconstruction of war-torn Iraq, in cooperation with the World Bank and private companies, it said Monday.

Deputy Foreign Minister Khaled al-Jarallah said that despite "past wounds" -- a reference to Iraq's 1990 invasion of Kuwait -- his country had a "moral, humanitarian and Arab" duty to support its neighbour.

"The stability of Iraq is the stability of Kuwait and the region," he said.

Iraqi forces have regained swathes of territory from the Islamic State group since the jihadists seized a third of Iraq and large parts of Syria in 2014.

In December, Baghdad declared victory over the group following three years of war.

The Kuwait conference, from February 12-14, will devote its second day to the role of the private sector and civil society organisations in reconstruction, Jarallah said.

Mehdi al-Alaq, the secretary general of Iraq's Council of Ministers, said Baghdad and the World Bank had estimated reconstruction would cost at least $100 billion (84 billion euros).

"ISIS displaced 5 million people," he said, speaking alongside Jarallah in Kuwait City.

"We succeeded in returning half to their areas, but we need international support to return the rest of the displaced."

The International Organization for Migration said last week that by the end of 2017, more than 3.2 million Iraqis had returned home, but 2.6 million remained displaced.

Nearly one third are reported to have returned to houses that have been significantly or completely damaged, it said.

Alaq said heavy damage had also affected oil, electricity, transport, communications and manufacturing infrastructure as well as basic services such as water and sanitation.

Some Iraqis have complained of delays by central authorities in launching reconstruction efforts.

Baghdad has argued that the world "owes" it a programme similar to the United States' multi-billion dollar post-war Marshall Plan for Europe.