The Organisation of Petroleum Exporting Countries (Opec) has confirmed that its members will not reduce production despite plummeting oil prices.

Senior Opec officials revealed that they are willing to let prices drop to $40 per barrel (bbl) before stepping in.

"We are not going to change our minds because the prices went to $60/bbl, or to $40/bbl," Suhail al-Mazrouei, energy minister of the United Arab Emirates told a Bloomberg conference in Dubai.

Opec members reiterated that the group would stand firm despite the price falls.

"The decision has been made. Things will be left as is," said Abdallah Salem el-Badri, secretary general of Opec.

"The fundamentals should not lead to this dramatic reduction [in price]. Some people say this decision was directed at the United States and shale oil. All of this is incorrect. Some also say it was directed at Iran and Russia. This also is incorrect," he said.

Brent crude oil plummeted to 2009 levels over the last few days and by 50% since June by falling below the $62/bbl) mark.

Meanwhile, US crude futures fell to $56.25/bbl on 15 December before rising back to $58.40/bbl.

The International Energy Agency warned that oil prices are set to fall further; some bank analysts predict a drop to $50/bbl.