The price for oil produced by the Organisation of the Petroleum Exporting Countries (OPEC) fell slightly on Tuesday, to $40, OPEC said on Wednesday.
One barrel (159 litres) of OPEC-produced crude was $0.24 lower than on the previous day.
The Vienna-based cartel could decide on further production cuts at its next meeting in March to support prices, OPEC Secretary General Abdalla Salem el-Badri indicated on Tuesday.
"If then the market is still over-supplied, the conference will not hesitate to take further measures to balance the market," he said in remarks published on OPEC's website.
So far, the cartel's 12 members were sticking to their production quotas, el-Badri said, following their decision in December to curb output by 2.2 million barrels per day.