A growing world food crisis is precipitating protectionist moves by countries which are likely to compound the problem and could lead to a wider trade war, business leaders and policymakers at the World Economic Forum said.

In a sign of the escalating squeeze on food supplies and rising prices, a government source told Reuters that India could restrict sugar exports for the first time in six years to prevent a surge in domestic prices.

Meanwhile Indonesia, the world's biggest palm oil exporter, will remove a subsidy on bulk cooking oil and replace it with a price cap on the raw materials for local refiners.

"It is a major issue, and frankly I think the problem is even bigger ahead of us than it is behind us," Gita Gopinath, first deputy managing director of the International Monetary Fund, told Reuters of rising food security concerns.

For residents in countries in Sub-Saharan Africa, for instance, 40 percent of their consumption is spent on food, Gopinath said. As well as a "huge hit to the cost of living," price rises have given rise to hoarding by governments.

Protectionism is looming large at Davos, prompting calls for urgent negotiations to avoid a full-blown trade war.

"It's very important for the leaders of the world to sit at the table with calm and talk about how we will manage trade and food and investment," Jay Collins, vice chairman of banking, capital markets and advisory at Citigroup told the Reuters Global Markets Forum in Davos.

The Russia-Ukraine crisis has led to a sudden crunch in a crisis that was already in the offing.

"We were facing an extraordinary food crisis before Ukraine, food costs, commodity prices, shipping costs were already doubling, tripling, quadrupling," David Beasley, executive director for the United Nations World Food Program, said.

The number of people "marching to starvation" has risen from 80 million to 276 million over the last four to five years, Beasley told Reuters in an interview in Davos.

"To keep the ports closed as the harvest season is now coming in Ukraine in July and August, it means a declaration of war on global food supply," he said.

(With input from Reuters)