Rice, the daily staple shared in family and communal food bowls across West Africa, risks becoming a luxury as rocketing price rises squeeze the pockets and stomachs of the region's people.

Prices for the commodity have soared this year, part of a wave of increases for major food cereals which humanitarian experts say is a threatening a "silent tsunami" of hunger and increased hardship for the world's poor, especially in Africa.

Fanned by the price hikes, food riots have flared like a trail of gunpowder through West Africa, sending governments scrambling to curb food exports, ease taxes on imports and increase subsidies for basic staples.

West African leaders are also dusting off often-delayed plans to boost domestic food farming, long sacrificed to imports.

From Nouakchott to Ouagadougou and N'Djamena and further south in Lagos and Kinshasa, ordinary West Africans are feeling the impact on tight daily budgets of more expensive rice - multiplied by higher costs of fuel and other basic staples.

"It's really tough. The kilogram of rice that I used to buy for 300 CFA francs ($0.73) now costs 350 CFA. Since everything else has gone up as well, you can't make ends meet any more," said Odile Zongo, a domestic worker in Burkina Faso's capital Ouagadougou.

Eric Hazard, Oxfam International's regional campaign manager for economic justice in West Africa, said most ordinary people in the region were already spending between 50 to 80 per cent of their income on food, so the price spikes were really hurting.

"Those living on the edge are particularly vulnerable to these high food prices," Hazard said.

In Senegal, which with Nigeria and Ivory Coast is among the world's top rice importers, the increases threaten to put the traditional midday rice meal out of reach of the poor.

"It's difficult, because rice is the base of all our dishes. We eat it with fish, meat and chicken," said Nafissatou Ndiaye, who runs a canteen kitchen serving 50 customers a day in Dakar.

"I already had to put prices up. I don't dare do it again, because I'll lose my clients," she said, pointing to the pink 25kg bags of "Thai Flavour" imported rice that she buys locally.

Rice from Thailand, the world's top exporter, has more than doubled in price this year. Experts point to a cocktail of factors, from export curbs in major producing states and rising demand to high fuel costs and erratic weather hitting harvests.

Ndiaye said the price of a 25kg bag of Thai rice had risen to nearly 7,000 CFA francs from 6,000 CFA francs last year.

The hike is not as sharp as it could be, as people are shielded from the full impact by official subsidies costing the Senegalese government several hundred million dollars.

Elsewhere in West Africa, the rises have been even sharper. In Kinshasa, Democratic Republic of Congo's capital, a 25kg bag of rice that cost $15 in November now sells for $25.

The higher costs are forcing many Africans to either reduce their rice consumption, or to change their diets. "People are eating more foufou (manioc paste), pondu (manioc leaves) or bread. They're eating what's cheapest," said Jean Fatuma, who sells imported rice in Kinshasa's Gambela market.

Some consumers in the region said they would be forced to cut back the family food intake to just one meal a day. "I cannot feed myself even though I am working for the state," said James Arthur William, a Sierra Leone civil servant.

Although the world's poorest continent is no stranger to famines, the rocketing food price inflation has set off alarm bells at the United Nations and humanitarian agencies.

The UN World Food Programme says it could push 100 million people into hunger. The UN special rapporteur on the right to food, Jean Ziegler, has called the trend "silent mass murder".

Many West African governments, seeing their people take to the streets to