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 below $63 a barrel, its lowest price since July 2009.
The price of Brent fell by $1.83 to $61.85 a barrel, hitting lows last seen in July 2009. Meanwhile, US crude was down $2.14 to $57.81 a barrel, its weakest since May 2009.
The IEA cut its forecast for global oil demand growth next year by 230,000 barrels per day to 900,000 barrels per day on the expectation of lower fuel consumption in Russia and other oil-exporting countries.
Oil prices have been in steep decline since June due to slow demand growth and a US shale oil boom which has increased supply.
Prices “continued to plunge in November and into early December”, the IEA said, adding that, “it may well take some time for supply and demand to respond to the price rout”.
The root cause of the fall in prices was “a surge in non‐Opec supply to its highest growth ever and contraction in demand growth to five‐year lows”.
It predicted that non-Opec supply gains would add to a global glut of oil.
The US boom should push non-Opec production to a record 1.9 million barrels per day this year, IEA said, but this figure should fall to 1.3 million barrels per day in 2015.
In Russia, the IEA said lower global oil prices combined with the effect of sanctions and a “collapsing currency” were likely to have an adverse effect on production.