The price of oil fell after a report from the International Energy Agency predicted weaker demand in 2015.
The IEA, a consultancy to 29 countries, said supply and demand would take “some time” to respond to sharp falls in oil prices.
It said it was too early to expect low oil prices to start constricting a US supply boom.
On Friday, Brent crude fell to around $63 a barrel, its lowest price since July 2009.
“Barring a disorderly production response, it may well take some time for supply and demand to respond to the price rout,” the IEA said.
Oil prices “continued to plunge in November and into early December” it said.