Thousands of supporters of Iraqi cleric Moqtada Sadr gathered at a mosque in east Baghdad on Friday for the first weekly prayers since the onset of the COVID-19 pandemic.

Iraq's mosques have been closed to gatherings for close to six months, but notoriously outspoken Sadr said on Wednesday that he would hold open-air prayers in his stronghold.

In east Baghdad's Sadr City on Friday, worshippers put on medical masks and gloves and had their temperatures taken before being allowed into the courtyard of the main mosque, where volunteers were spraying disinfectant.

"We urge everyone to abide by social distancing and protect themselves against this virus," the imam said in the opening to his brief sermon.

Sadr had issued a list of restrictions on Twitter this week, including that worshippers must stand exactly 75 centimetres apart and sermons must last only 15 minutes.

One worshipper, Qassem Al Mayahi, 40, said he was "happy to finally be able to pray on Fridays, as this is one of the five pillars of Islam".

"We need to figure out how to live" with the virus, he told AFP. "We may as well pray."

Other prayers at Sadrist mosques were expected in the Shiite holy city of Najaf on Friday.

The coronavirus pandemic has hit Iraq hard, with nearly 280,000 confirmed cases and more than 7,800 deaths.

In March, Iraqi authorities shut down airports and imposed total lockdowns to halt the virus's spread. Top Shiite authority Grand Ayatollah Ali Sistani halted his weekly sermons, and they have yet to resume.

But rules have generally been relaxed, with most airports reopening in July and curfews now only in place overnight.

On Monday, the Iraqi government's coronavirus crisis cell announced restaurants could seat customers — rather than just providing takeaway services — if they abide by health ministry protocols and that sports events could resume, but in the absence of spectators.

The loosening of restrictions came just a few days after Iraq recorded its highest daily caseload yet, with more than 5,000 new Covid-19 infections recorded on September 4.

The health ministry attributed the spike to recent "large gatherings" that took place without recommended safety measures, including mask wearing and social distancing.

That included the marking on August 30 of Ashura, a Shiite day of mourning that commemorates the killing of the Prophet Mohammed's grandson Hussein in Karbala in 680AD.

Usually, millions of pilgrims from around the world travel to Karbala to mark Ashura, but this year Iraq did not grant visas to religious tourists and kept borders with neighbouring Shiite-majority Iran closed.

But concern is already building over Arbaeen, which comes 40 days after Ashura — on October 8 — and typically sees even larger numbers converge at Karbala.

Iraq's interior ministry told AFP any foreign national without Iraqi residency would not be granted entry until after Arbaeen.

Hospitals in Iraq have already been worn down by decades of conflict and poor investment, with shortages in medicines, hospital beds and even protective equipment for doctors.