Davos, Switzerland - The drop in the price of oil is a result of the global economic downturn, energy chiefs said Thursday, but the fall has been too great and the current amount will not leave producing countries with enough capital for investment.

"The price is low because demand has fallen, because economic growth in most part of the world has stopped," said Tony Hayward, the head of BP.

"When economic recovery returns demands will come back very fast," he added at the World Economic Forum's session on energy outlook for the upcoming year.

He warned that if prices remain low, and producing countries do have resources to invest in increased capacity, the world would run into supply constraints.

"We are not very happy with 40, even 50" dollars a barrel, said Abdalla Salem el Badri, the secretary general of the Organization of Petroleum Exporting Countries (OPEC).

"We cannot have decent income for our member countries and at the same time invest for additional capacity. I hope price will pick up, to go a little bit higher," said the head of the oil cartel, noting that at the next meeting of the group it would not hesitate to act to boost prices.

On Thursday, crude rates stood at 42 dollars a barrel.

"Investment is the name of the game," he emphasized.

El-Badri and Hayward said they hoped that the various stimulus packages being introduced around the world, from China to the US, would create a hike in the price of oil.

The previous night Russian leader Vladimir Putin said "sharp and unpredictable fluctuations of energy prices are a colossal destabilising factor in the global economy," and pushed for a "new international legal framework for energy security."

Mukesh Ambani, the chairman of Reliance Industries in India, said at the energy session that there was no end to oil in the next decades, and added that the "bridge to de-carbonized world" must be built in a "sensible way." (dpa)