Egypt's state news agency says a 10-year-old girl who was critically wounded in the suicide bombing at a Cairo church earlier this month, has died of her wounds.

The fatality raises the death toll from the attack to 27.

Egypt's ISIS affiliate has claimed responsibility for the bombing, though authorities blamed the banned Muslim Brotherhood group.

The little girl, Maggie Mamoun, became the face of the Coptic community's grief in the days following the horrific bombing, with photos of the smiling child circulating on social media, along with prayer requests.

The MENA news agency said on Tuesday that her funeral will be held at the church that was bombed.

The attack was the worst in living memory on Egypt's Christians, who make up nearly 10 per cent of the population.