Ebola has now infected more than 1 000 people in the Democratic Republic of Congo in an outbreak that has spread to a third displacement camp and killed an 18-month-old girl, official reports showed.

The confirmed death count stood at 254, Congo's government said late on Sunday, more than a month after the declaration of the outbreak of the rare Bundibugyo strain that has no approved ⁠treatment or vaccine.

The speed of its spread across three provinces of eastern Congo has prompted warnings from African health experts that the outbreak could eventually surpass the epidemic that killed more than 11 000 people across West Africa from 2014 to 2016.

The girl was tested for Ebola on June 14 in the Hungbe displacement camp, and died before the positive result came back the next day, a Congolese health report seen by Reuters showed.

She had developed a fever more than a week earlier, and was carried on foot to two different health centres and given antibiotics before finally getting tested, a Congolese official and the report said.

At least 107 people came into contact with her, including family members, healthcare workers and people from other camps, it added.

There was a shortage of facilities to isolate patients, Dr Emmanuel Musingusi Bulemu, a Congolese health official in the surrounding Nizi zone, said.

"We need to separate these patients from the community because they risk infecting others but where can we put them?," he added.

There have also been two confirmed cases in Kpangba, another displacement camp in the same area housing people who have fled decades of conflict between armed groups, militias and the army.

At least 30 people have died in a camp in another displacement site in Bunia.

So far, nearly a fifth of confirmed cases have been children, according to preliminary data from the U.N. children's agency UNICEF.

A much smaller number of cases have also been reported in neighbouring Uganda.