A drought is threatening Angola's already modest food production, in a setback for efforts to revive once-vibrant farmlands abandoned during decades of war.

The dry season that normally lasts only about three weeks in December has stretched to three months in parts of the southern African country where most regions are used to abundant rainfall almost year-round.

The government has promised to help farmers, mostly smallholders producing for their own survival, but most of that aid has yet to materialise.

"Production has collapsed throughout the central and southern regions," said Belarmino Jelembi, national coordinator of the Association for Rural and Environmental Development.

That means a loss of revenue, but also "a threat of famine for families", he said.

During Portuguese colonial times, plantations and family farms made Angola a leading exporter of coffee, bananas and sisal, while growing enough food to meet most of its needs.

Most of the nation's farms were abandoned during decades of liberation battles and then a bloody civil war that ended only 10 years ago.

During the conflict, Angolans fled the countryside for the relative safety of the cities, leaving behind fields littered with landmines. In recent years, some areas have been cleared enough for farming to resume.

Government wants to increase domestic food production to ease Angola's dependence on expensive imports -- one of the main factors in the country's sky-high cost of living that makes life in Luanda more expensive than Tokyo.

Global risk consultancy Maplecroft last year ranked Angola as fifth in the world for unstable food supplies, placing it among troubled nations like Somalia.

The main opposition party Unita faults the government for failing to invest enough in Angola's farms. Since the end of the war, Africa's second-largest oil producer has emerged as one of the world's fastest-growing economies.

But that wealth hasn't reached the majority of the population, who still live in poverty.

Regional guidelines "recommend spending 10 percent of the national budget on the agricultural sector," said Unita secretary general Vitorino Nhany.

Government figures show the amount is actually five percent, and Nhany claims the true figure is only 1.2 percent.

The drought could make life even more difficult for Angola's poor, as production drops for staple crops like cereals, beans and sweet potatoes.

The most affected are Angola's two million small farmers, who depend on rain for their crops to survive, said Jelembi.

"Dependence on rain is the main problem for our farms," Jelembi said, warning of food shortages and rising prices later this year.

The hardest hit regions are provinces around the second city of Huambo -- Benguela, Huambo, Bie and Huila. The northern provinces of Zaire and Uige have also been affected, but to lesser degree.

The government unveiled a farm aid scheme in March, offering new seeds to try to recover lost production. Authorities also promised to launch irrigation projects, and to re-finance farm loans.

The plans called for "distribution of food and farm goods, as well as providing water by cisterns".

Over the long term, Angola wants to stop growing tubers, which consume lots of water, with plants less dependent on rains.

Jelembi's group supports these measures, but he said the government "systematically launches projects ill-suited to the needs and abilities of local communities.

"For example, on developing irrigation, the government wants to build a series of major dams, when all we're asking for is aid in building a network of small dams that farmers could manage themselves," he said.