Afghanistan's food crisis is a "legacy" of the previous government, the Taliban deputy health minister said Monday, as he accused the international community of failing to keep its promises of aid.

The UN has warned that around 22 million Afghans or half the country will face an "acute" food shortage in the winter months due to the combined effects of drought caused by global warming and an economic crisis aggravated by the Taliban takeover. 

"There is a very important problem that has been left over as a legacy from the former regime, and that is malnutrition," Deputy Health Minister Abdul Bari Omar said at a press conference in Kabul. 

He cited World Food Programme figures showing 3.2 million Afghan children under the age of five will be acutely malnourished by the end of the year, and said the previous US-backed government did not do enough to avert disaster.

"For twenty years, the health sector has remained dependent on foreign aid. No basic work has been done ... so the healthcare infrastructure and its resources could survive," he said.

Foreign donors and non-governmental organisations have financed everything, he continued, adding: "No factories have been built, the domestic resources haven't been utilised."

The Taliban overthrew the previous US-backed government on August 15 following a lightning offensive into the capital. 

The international community then froze the aid on which the country's economy so heavily relied.

"How we can provide services if the foreign resources are curtailed and the international organisations cut their aid?" Omar said. 

"The World Bank, EU, and USAID (the US development agency) do not fulfil the promises they made to the people of Afghanistan," he said.

"Organisations made commitments to the people of Afghanistan, and made promises to mothers, children, and the needy. Their slogan was to keep health services away from politics, but when the (regime) change took place, unfortunately, they all ended up with a political agenda," he said. 

The food crisis comes after Afghanistan has already been devastated by more than four decades of conflict.