Aid agencies are warning that the humanitarian crisis in Mozambique is likely to worsen before it improves.

The Mozambican Goverment and the United Nations have launched an urgent $13m appeal for immediate humanitarian aid, as a tropical cyclone compounded the effects of earlier flooding.

Hundreds of thousands of people are estimated to be at risk, primarily from diseases.

And analysts suggest that Mozambique is likely to be dependent on food aid for at least the next six months.

The government has asked for more than $65m (£40m) to help to rebuild the country's roads, bridges and power supplies, once the floods subside.

Carol Bellamy, the executive director of the UN Children's Fund (Unicef) says agencies cannot put an exact figure on the amount of aid needed, but makes it clear the crisis is worsening.

"It's an absolute disaster. This country was one of the success stories - but what a knock-down blow," she said.

"The impact is both immediate and will be long-standing. I don't think you can estimate how long it is going to take them to recover."

Aid workers have warned that cholera, malaria and meningitis are all likely to hit, and the hundreds of thousands driven to cramped refuge on high ground are most at risk.

Water-borne diseases have already begun claiming their first victims.

Logistical nightmare

With much of Mozambique submerged beneath muddy water, aid can only be delivered by air - a logistical nightmare.

Once food can be got through, the UN's relief arm, the World Food Programme, say they only have enough food stockpiled to feed about 300,000 displaced people for three months.

Unicef's Ian Macleod in the capital, Maputo, told the BBC that the immediate priority for Unicef is to try to get vaccines delivered around the country to tackle the threat of disease - and transport is urgently needed to do this.

Currently, he says only three South African helicopters are delivering food aid and emergency supplies to the hundreds of thousands of people trapped by floods in Mozambique.

French planes have also been ferrying material to larger towns from Maputo, but help from other nations is slow to materialise - even more than two weeks after the floods began.

Many remote areas have still to be reached.

The fear is that disease will have claimed a significant number of lives by then, in a country that was just finding its feet after being ravaged by a 15-year civil war.