Authorities temporarily shut the airports in the southern provinces of Najaf and Basra as the sandstorm -- the biggest this year -- obscured visibility in an eery orange cloud.

Iraq, which endures blistering summer heat and regular sandstorms, is one of the five countries most impacted by some effects of climate change, says the United Nations.

Hospitals in Muthanna province in southern Iraq received at least "700 cases of suffocation", local health official Mazen al-Egeili said.

More than 250 people were hospitalised in Najaf province, according to its health directorate.

An AFP photographer in Najaf saw police officers and pedestrians wearing face masks to shield themselves from the suffocating cloud of dust that hung heavily in the air.

Inside a nearby ambulance, a paramedic assisted a young man who was gasping for air.

At least 322 patients including children flocked to hospitals in Diwaniyah province, said Amer al-Kinani, the provincial health department's media officer.

In Dhi Qar and Basra provinces more than 530 people had breathing problems, local health officials said.

The sandstorm drastically reduced visibility to less than one kilometre (0.62 mile) but it is expected to gradually dissipate by Tuesday morning, weather services said.

In 2022, one person died and more than 5,000 were treated in hospitals for respiratory ailments due to a heavy sandstorm in Iraq.

The environment ministry has warned the country can expect to experience a rising number of "dust days" in coming decades.