A health worker inspects a babys' feet before entering a cholera treatment centre in Beira, Mozambique. Picture: Tsvangirayi Mukwazhi/AP

Maputo - Authorities in flood-ravaged Mozambique confirmed five cases of cholera on Wednesday, after aid groups warned of a possible outbreak of the waterborne disease in the wake of cyclone Idai.

Ussene Issa, National Director of Medical Assistance, confirmed the cases of cholera to dpa by phone, saying all five were reported in the Munhava area of Beira.

The World Health Organization (WHO) has already shipped some 900,000 doses of an oral cholera vaccine to Mozambique. The WHO is also providing expertise to set up three cholera treatment centres, including an 80-bed facility in Beira.

"Given the sheer amount of water that passed through Beira during cyclone Idai and the volume of damage caused, it's not surprising that there are outbreaks of waterborne disease like cholera in the city," the charity Doctors Without Borders said in a statement Wednesday.

The UN also warned of the risk of diarrhoea and malaria.

"Flood waters are beginning to recede west of Beira City... The outflow of flood waters, however, poses new challenges, as the area that was previously underwater is now a large muddy swamp," the UN Office for the Coordination of Humanitarian Affairs (OCHA) said in a statement.

"The risk of water-borne and vector-borne diseases remains very high and there are reports of increasing cases of acute watery diarrhoea, along with reports of malaria," it added.

It has been almost two weeks since the cyclone hit southern Africa, with Mozambique bearing the brunt but parts of Zimbabwe and Malawi also devastated.

More than 700 people have died in the three countries combined, and hundreds of thousands are displaced. The death toll is expected to rise considerably.

At least 3 million people have been affected in total, according to UN figures, by what has been called one of the worst cyclone-related disasters ever to hit the Southern Hemisphere.

On Wednesday, the first of three planes from the UN refugee agency (UNHCR) carrying relief items like tents, plastic tarpaulins, blankets, mosquito nets, and solar lanterns landed in Mozambique.

Two more planes will be sent to Malawi and Zimbabwe.

"Survivors of this devastating natural disaster are in dire need of global support," said Valentin Tapsoba, UNHCR Director for Southern Africa.

The UN World Food Programme on Wednesday also called on the international community to step up support, warning that the storm's victims would need at least six months to get back on their feet.

The WFP said it requires 140 million dollars for the next three months to help with food delivery efforts and sending support staff.

Aside from food aid and disease prevention, the UN is setting up temporary learning spaces for children, as well as safe spaces for women who have been displaced and may be at risk of gender-related violence, OCHA said.

dpa