Baghdad (AFP) - More than 1,000 members of the Iraqi forces have been wounded since the start of the operation to retake Fallujah from the Islamic State group, a health official said Friday.

"We have received 1,119 wounded since the start of the operation," a senior Baghdad health official told AFP on condition of anonymity.

"The wounded fighters were treated at Kadhimiya, Abu Ghraib, Al Karama, Al Karkh and Yarmuk hospitals," he said.

The official said the casualty toll included members of the army, police, counter-terrorism service and Hashed al-Shaabi paramilitary organisation.

Iraqi forces on May 22-23 launched a vast offensive aimed at retaking the IS bastion of Fallujah, a city only 50 kilometres (30 miles) west of Baghdad that was the first to fall out of government control in 2014.

Iraqi military commanders are not divulging casualty figures.

The health official could not provide a figure for the number of fighters killed.

The bodies of the dead are usually taken to a morgue near Baghdad airport or other locations and then collected directly by the families.

The number of funerals held across the country however suggests the Fallujah battle is taking a high toll.

The coffins of at least 70 fighters killed in the Fallujah fighting had by Wednesday been brought to Najaf's Valley of Peace cemetery, where many from Iraq's Shiite majority bury their dead, according to a security source there.

Officials in Basra said the southern province had lost 26 fighters from the Hashed al-Shaabi force alone.

Commanders say that since elite forces backed by police and army moved to the fringes of the city centre, IS has put up fierce resistance.