“Irresponsible” levels of output by producers from outside the OPEC oil cartel is among the main causes of the slump in prices, the United Arab Emirates energy minister charged Sunday.

“One of the main causes is irresponsible production by some producers from outside the organisation, some of whom are newcomers,” Suhail al-Mazrouei told an energy forum in Abu Dhabi.

Mazrouei said the sharp drop in prices will impose a “major economic burden” on oil producing countries, insisting nonetheless that OPEC’s decision last month to maintain output levels was “correct.”

“OPEC’s decision, which aims to provide the market with time to rebalance, is correct, strategic and useful to the global economy,” he said at the forum organised by the Organisation of Arab Petroleum Exporting Countries.

The OPEC decision will “lead to stability in oil prices,” he said.

His optimism coincided with Saudi Oil Minister Ali al-Naimi’s who also said Sunday he was confident world prices would improve after a slide he blamed partly on “lack of cooperation” by producers outside the OPEC cartel.

“I am confident that oil markets will recover… and that oil prices will improve,” Naimi told the energy forum in Abu Dhabi.

He said the sharp drop in prices was partly due to the “lack of cooperation by main producing countries outside OPEC, misleading information and speculators’ greed.”

World prices have fallen almost 50 percent since June, mainly due to a supply glut, the weak global economy and a strong US dollar.